Many of the differences between American and British English date back to a time when spelling standards had not yet developed. For instance, some spellings seen as "American" today were once commonly used in Britain and some spellings seen as "British" were once commonly used in the United States. A "British standard" began to emerge following the 1755 publication of Samuel Johnson's A Dictionary of the English Language, and an "American standard" started following the work of Noah Webster and in particular his An American Dictionary of the English Language, first published in 1828.
Webster's efforts at spelling reform were somewhat effective in his native country, resulting in certain well-known patterns of spelling differences between the American and British varieties of English. However, English-language spelling reform has rarely been adopted otherwise, and so modern English orthography varies somewhat between countries and is far from phonemic in any country.
In the early 18th century, English spelling was inconsistent. These differences became noticeable after the publishing of influential dictionaries. Today's British English spellings mostly follow Johnson's A Dictionary of the English Language (1755), while many American English spellings follow Webster's An American Dictionary of the English Language ("ADEL", "Webster's Dictionary", 1828).
Webster was a proponent of English spelling reform for reasons both philological and nationalistic. In A Companion to the American Revolution (2008), John Algeo notes: "it is often assumed that characteristically American spellings were invented by Noah Webster. He was very influential in popularizing certain spellings in America, but he did not originate them. Rather […] he chose already existing options such as center, color and check for the simplicity, analogy or etymology". William Shakespeare's first folios, for example, used spellings like center and color as much as centre and colour. Webster did attempt to introduce some reformed spellings, as did the Simplified Spelling Board in the early 20th century, but most were not adopted. In Britain, the influence of those who preferred the Norman (or Anglo-French) spellings of words proved to be decisive. Later spelling adjustments in the United Kingdom had little effect on today's American spellings and vice versa.
For the most part, the spelling systems of most Commonwealth countries and Ireland closely resemble the British system. In Canada, the spelling system can be said to follow both British and American forms, and Canadians are somewhat more tolerant of foreign spellings when compared with other English-speaking nationalities. Australian spelling has also strayed slightly from British spelling, with some American spellings incorporated as standard. New Zealand spelling is almost identical to British spelling, except in the word fiord (instead of fjord). There is also an increasing use of macrons in words that originated in Māori and an unambiguous preference for -ise endings (see below).
Most words ending in an unstressed -our in British English (e.g., colour, flavour, behaviour, harbour, honour, humour, labour, neighbour, rumour, splendour) end in -or in American English (color, flavor, behavior, harbor, honor, humor, labor, neighbor, rumor, splendor). Wherever the vowel is unreduced in pronunciation, e.g., contour, velour, paramour and troubadour the spelling is consistent everywhere.
Most words of this kind came from Latin, where the ending was spelled -or. They were first adopted into English from early Old French, and the ending was spelled -or or -ur. After the Norman conquest of England, the ending became -our to match the Old French spelling. The -our ending was not only used in new English borrowings, but was also applied to the earlier borrowings that had used -or. However, -or was still sometimes found, and the first three folios of Shakespeare's plays used both spellings before they were standardised to -our in the Fourth Folio of 1685. After the Renaissance, new borrowings from Latin were taken up with their original -or ending and many words once ending in -our (for example, chancellour and governour) went back to -or. Many words of the -our/or group do not have a Latin counterpart; for example, armo(u)r, behavio(u)r, harbo(u)r, neighbo(u)r; also arbo(u)r, meaning "shelter", though senses "tree" and "tool" are always arbor, a false cognate of the other word. Some 16th- and early 17th-century British scholars indeed insisted that -or be used for words from Latin (e.g., color) and -our for French loans; but in many cases the etymology was not clear, and therefore some scholars advocated -or only and others -our only.
Webster's 1828 dictionary had only -or and is given much of the cr for the adoption of this form in the United States. By contrast, Johnson's 1755 (pre-U.S. independence and establishment) dictionary used -our for all words still so spelled in Britain (like colour), but also for words where the u has since been dropped: ambassadour, emperour, governour, perturbatour, inferiour, superiour; errour, horrour, mirrour, tenour, terrour, tremour. Johnson, unlike Webster, was not an advocate of spelling reform, but chose the spelling best derived, as he saw it, from among the variations in his sources. He preferred French over Latin spellings because, as he put it, "the French generally supplied us". English speakers who moved to America took these preferences with them, and H. L. Mencken notes that "honor appears in the 1776 Declaration of Independence, but it seems to have got there rather by accident than by design. In Jefferson's original draft it is spelled "honour". In Britain, examples of color, flavor, behavior, harbor, and neighbor rarely appear in Old Bailey court records from the 17th and 18th centuries, whereas there are thousands of examples of their -our counterparts. One notable exception is honor. Honor and honour were equally frequent in Britain until the 17th century; honor still is, in the UK, the usual spelling as a person's name and appears in Honor Oak, a district of London.
In derivatives and inflected forms of the -our/or words, British usage depends on the nature of the suffix used. The u is kept before English suffixes that are freely attachable to English words (for example in neighbourhood, humourless, and savoury) and suffixes of Greek or Latin origin that have been adopted into English (for example in favourite, honourable, and behaviourism). However, before Latin suffixes that are not freely attachable to English words, the u:
American usage, in most cases, keeps the u in the word glamour, which comes from Scots, not Latin or French. Glamor is sometimes used in imitation of the spelling reform of other -our words to -or. Nevertheless, the adjective glamorous often drops the first "u". Saviour is a somewhat common variant of savior in the US. The British spelling is very common for honour (and favour) in the formal language of wedding invitations in the US. The name of the Space Shuttle Endeavour has a u in it as the spacecraft was named after Captain James Cook's ship, HMS Endeavour. The special car on Amtrak's Coast Starlight train is known as the Pacific Parlour car, not Pacific Parlor. Proper names such as Pearl Harbor or Sydney Harbour are usually spelled according to their native-variety spelling vocabulary.
The name of the herb savory is thus spelled everywhere, although the related adjective savo(u)ry, like savo(u)r, has a u in the UK. Honor (the name) and arbor (the tool) have -or in Britain, as mentioned above. As a general noun, rigour // has a u in the UK; the medical term rigor (sometimes //) does not, such as in rigor mortis, which is Latin. Derivations of rigour/rigor such as rigorous, however, are typically spelled without a u even in the UK. Words with the ending -irior, -erior or similar are spelled thus everywhere.
Commonwealth countries normally follow British usage. Canadian English most commonly uses the -our ending and -our- in derivatives and inflected forms. However, owing to the close historic, economic, and cultural relationship with the United States, -or endings are also sometimes used. Throughout the late 19th and early to mid-20th century, most Canadian newspapers chose to use the American usage of -or endings, originally to save time and money in the era of manual movable type. However, in the 1990s, the majority of Canadian newspapers officially updated their spelling policies to the British usage of -our. This coincided with a renewed interest in Canadian English, and the release of the updated Gage Canadian Dictionary in 1997 and the first Oxford Canadian Dictionary in 1998. Historically, most libraries and educational institutions in Canada have supported the use of the Oxford English Dictionary rather than the American Webster's Dictionary. Today, the use of a distinctive set of Canadian English spellings is viewed by many Canadians as one of the cultural uniquenesses of Canada (especially when compared to the United States).
In Australia, -or endings enjoyed some use throughout the 19th century and in the early 20th century. Like Canada, though, most major Australian newspapers have switched from "-or" endings to "-our" endings. The "-our" spelling is taught in schools nationwide as part of the Australian curriculum. The most notable countrywide use of the -or ending is for the Australian Labor Party, which was originally called "the Australian Labour Party" (name adopted in 1908), but was frequently referred to as both "Labour" and "Labor". The "Labor" was adopted from 1912 onward due to the influence of the American labor movement and King O'Malley. Aside from that, -our is now almost universal in Australia. New Zealand English, while sharing some words and syntax with Australian English, follows British usage.
In British English, some words from French, Latin or Greek end with a consonant followed by an unstressed -re (pronounced /ə(r)/). In American English, most of these words have the ending -er. The difference is most common for words ending -bre or -tre: British spellings calibre, centre, fibre, goitre, litre, lustre, manoeuvre, meagre, metre, mitre, nitre, ochre, reconnoitre, sabre, saltpetre, sepulchre, sombre, spectre, theatre (see exceptions) and titre all have -er in American spelling.
In Britain, both -re and -er spellings were common before Johnson's dictionary was published. In Shakespeare's first folios, -er spellings are used the most. Most English words that today use -er were spelled -re at one time. In American English, almost all of these have become -er, but in British English only some of them have. Words that were once spelled -re include chapter, December, disaster, enter, filter, letter, member, minister, monster, November, number, October, offer, oyster, powder, proper, September, sober and tender. Words using the "-meter" suffix (from ancient Greek -μέτρον via post-Classical Latin meter) have normally had the -er spelling from earliest use in English. Examples include thermometer and barometer.
The e preceding the r is kept in American inflected forms of nouns and verbs, for example, fibers, reconnoitered, centering, which are fibres, reconnoitred, and centring respectively in British English. Centring is an interesting example, since, according to the OED, it is a "word ... of 3 syllables (in careful pronunciation)" (i.e., /ˈsɛntərɪŋ/), yet there is no vowel in the spelling corresponding to the second syllable (/ə/). The three-syllable version is listed as only the American pronunciation of centering on the Oxford Dictionaries Online website. The e is dropped for other derivations, for example, central, fibrous, spectral. However, the existence of related words without e before the r is not proof for the existence of an -re British spelling: for example, entry and entrance come from enter, which has not been spelled entre for centuries.
The difference relates only to root words; -er rather than -re is universal as a suffix for agentive (reader, winner, user) and comparative (louder, nicer) forms. One outcome is the British distinction of meter for a measuring instrument from metre for the unit of length. However, while "poetic metre" is often -re, pentameter, hexameter etc. are always -er.
Many other words have -er in British English. These include Germanic words; such as anger, mother, timber and water and Romance words danger, quarter and river.
The ending -cre, as in acre, lucre, massacre, and mediocre, is used in both British and American English to show that the c is pronounced /k/ rather than /s/. The spellings ogre and euchre are also the same in both British and American English.
Theater is the prevailing American spelling used to refer to both the dramatic arts and buildings where stage performances and screenings of films take place (i.e., "movie theaters"); for example, a national newspaper such as The New York Times would use theater in its entertainment section. However, the spelling theatre appears in the names of many New York City theaters on Broadway (cf. Broadway theatre) and elsewhere in the United States. In 2003, the American National Theatre was referred to by The New York Times as the "American National Theater", but the organization uses "re" in the spelling of its name. The John F. Kennedy Center for the Performing Arts in Washington, D.C. has the more common American spelling theater in its references to The Eisenhower Theater, part of the Kennedy Center. Some cinemas outside New York also use the theatre spelling. (Note also that the word "theater" in American English is a place where stage performances and screenings of films take place, but in British English a "theatre" is where stage performances take place but not film screenings – these take place in a cinema.)
Furthermore, the spelling theatre is sometimes used in the United States when referring to the art form of theatre, while the building itself, as noted above, generally is spelled theater. For example, the University of Wisconsin-Madison has a "Department of Theatre and Drama", which offers courses that lead to the "Bachelor of Arts in Theatre", and whose professed aim is "to prepare our graduate students for successful 21st Century careers in the theatre both as practitioners and scholars".
Some placenames in the United States use Centre in their names. Examples include the Stonebriar Centre mall, the cities of Rockville Centre and Centreville, Centre County and Centre College. Sometimes, these places were named before spelling changes but more often the spelling merely serves as an affectation.
For British accoutre, the American practice varies: the Merriam-Webster Dictionary prefers the -re spelling, but The American Heritage Dictionary of the English Language prefers the -er spelling.
More recent French loanwords keep the -re spelling in American English. These are not exceptions when a French-style pronunciation is used (/rə/ rather than /ə(r)/), as with double entendre, genre and oeuvre. However, the unstressed /ə(r)/ pronunciation of an -er ending is used more (or less) often with some words, including cadre, macabre, maître d', Notre Dame, piastre, and timbre.
The -re endings are mostly standard throughout the Commonwealth. The -er spellings are recognized as minor variants in Canada, partly due to American influence, and are sometimes used in proper names (such as Toronto's controversially named Centerpoint Mall).
For advice/advise and device/devise, American English and British English both keep the noun–verb distinction both graphically and phonetically (where the pronunciation is -/s/ for the noun and -/z/ for the verb). For licence/license or practice/practise, British English also keeps the noun–verb distinction graphically (although phonetically the two words in each pair are homophones with -/s/ pronunciation). On the other hand, American English uses license and practice for both nouns and verbs (with -/s/ pronunciation in both cases too).
American English has kept the Anglo-French spelling for defense and offense, which are defence and offence in British English. Likewise, there are the American pretense and British pretence; but derivatives such as defensive, offensive, and pretension are always thus spelled in both systems.
Australian and Canadian usage generally follows British.
The spelling connexion is now rare in everyday British usage, its use lessening as knowledge of Latin lessens, and it is not used at all in the US: the more common connection has become the standard worldwide. According to the Oxford English Dictionary the older spelling is more etymologically conservative, since the original Latin word had -xio-. The American usage comes from Webster, who abandoned -xion and preferred -ction. Connexion was still the house style of The Times of London until the 1980s and was still used by the British Post Office for its telephone services in the 1970s, but had by then been overtaken by connection in regular usage (for example, in more popular newspapers).
Complexion (which comes from complex) is standard worldwide and complection is rare. However, the adjective complected (as in "dark-complected"), although sometimes objected to, is standard in the US as an alternative to complexioned, but is not used in this way in the UK, although there is a rare usage to mean complicated.
In some cases, words with "old-fashioned" spellings are retained widely in the US for historical reasons (cf. connexionalism).
Many words, especially medical words, that are written with ae/æ or oe/œ in British English are written with just an e in American English. The sounds in question are /iː/ or /ɛ/ (or, unstressed, /i/, /ɪ/ or /ə/). Examples (with non-American letter in bold): aeon, anaemia, anaesthesia, caecum, caesium, coeliac, diarrhoea, encyclopaedia, faeces, foetal, gynaecology, haemoglobin, haemophilia, leukaemia, oesophagus, oestrogen, orthopaedic (Although in the U.S., the majority of college, university, and residency programs, and even the American Academy of Orthopaedic Surgeons, still use the spelling with the digraph ae, though hospitals usually use the shortened form.), palaeontology, paediatric, paedophile. Oenology is acceptable in American English but is deemed a minor variant of enology, whereas although archeology and ameba exist in American English, the British versions archaeology and amoeba are more common. The chemical haem (named as a shortening of haemoglobin) is spelled heme in American English, to avoid confusion with hem.
Words that can be spelled either way in American English include aesthetics and archaeology (which usually prevail over esthetics and archeology), as well as palaestra, for which the simplified form palestra is described by Merriam-Webster as "chiefly Brit[ish]."
Words that can be spelled either way in British English include encyclopaedia, homoeopathy, chamaeleon, mediaeval (a minor variant in both AmE and BrE), foetid and foetus. The spellings foetus and foetal are Britishisms based on a mistaken etymology. The etymologically correct original spelling fetus reflects the Latin original and is the standard spelling in medical journals worldwide, the Oxford English Dictionary notes that "In Latin manuscripts both fētus and foetus are used".
The Ancient Greek diphthongs <αι> and <οι> were transliterated into Latin as <ae> and <oe>. The ligatures æ and œ were introduced when the sounds became monophthongs, and later applied to words not of Greek origin, in both Latin (for example, cœli) and French (for example, œuvre). In English, which has adopted words from all three languages, it is now usual to replace Æ/æ with Ae/ae and Œ/œ with Oe/oe. In many words, the digraph has been reduced to a lone e in all varieties of English: for example, oeconomics, praemium, and aenigma. In others, it is kept in all varieties: for example, phoenix, and usually subpoena, but Phenix in Virginia. This is especially true of names: Caesar, Oedipus, Phoebe, etc. There is no reduction of Latin -ae plurals (e.g., larvae); nor where the digraph <ae>/<oe> does not result from the Greek-style ligature: for example, maelstrom, toe. The British form aeroplane is an instance (compare other aero- words such as aerosol). The now chiefly North American airplane is not a respelling but a recoining, modelled after airship and aircraft. The word airplane dates from 1907, at which time the prefix aero- was trisyllabic, often written aëro-.
The -ize spelling is often incorrectly seen as an Americanism in Britain, although it has been in use since the 15th century, predating -ise by over a century. However, the Oxford English Dictionary (OED) recommends -ize and notes that the -ise spelling is from French: "The suffix…whatever the element to which it is added, is in its origin the Greek -ιζειν, Latin -izāre; and, as the pronunciation is also with z, there is no reason why in English the special French spelling should be followed, in opposition to that which is at once etymological and phonetic." The OED lists the -ise form as an alternative.
Publications by Oxford University Press (OUP)—such as Henry Watson Fowler's A Dictionary of Modern English Usage, Hart's Rules, and The Oxford Guide to English Usage—also recommend -ize. However, Robert Allan's Pocket Fowler's Modern English Usage considers either spelling to be acceptable anywhere but the US. Also, Oxford University itself does not agree with the OUP, but advocates -ise instead of -ize in its staff style guide.
British spelling mostly uses -ise, while -ize is also used (organise/organize, realise/realize, recognise/recognize): the ratio between -ise and -ize stood at 3:2 in the British National Corpus up to 2002. The spelling -ise is more commonly used in UK mass media and newspapers, including The Times (which switched conventions in 1992), The Daily Telegraph and The Economist. Meanwhile, -ize is used in some British-based academic publications, such as Nature, the Biochemical Journal and The Times Literary Supplement. The minority British English usage of -ize is known as Oxford spelling and is used in publications of the Oxford University Press, most notably the Oxford English Dictionary, and of other academic publishers. It can be identified using the IETF language tag en-GB-oxendict (or, historically, by en-GB-oed).
In Canada, the -ize ending is more common, whereas in Ireland, India, Australia and New Zealand -ise spellings strongly prevail: the -ise form is preferred in Australian English at a ratio of about 3:1 according to the Macquarie Dictionary.
Worldwide, -ize endings prevail in scientific writing and are commonly used by many international organizations, such as the United Nations Organizations (such as the World Health Organization and the International Civil Aviation Organization) and the International Organization for Standardization (but not by the Organisation for Economic Co-operation and Development). The European Union's style guides require the usage of -ise. Proofreaders at the EU's Publications Office ensure consistent spelling in official publications such as the Official Journal (where legislation and other official documents are published), but the -ize spelling may be found in other documents.
Some verbs ending in -ize or -ise do not come from Greek -ιζειν, and their endings are therefore not interchangeable:
Some words spelled with -ize in American English are not used in British English, etc., e.g., the verb burglarize, regularly formed on the noun burglar, where the equivalent in British, and other versions of, English is the back-formation burgle and not burglarise.
Analyse seems to have been the more common spelling in 17th- and 18th-century English, but many of the great dictionaries of that time – John Kersey's of 1702, Nathan Bailey's of 1721 and Samuel Johnson's of 1755 – prefer analyze. In Canada, -yze prevails, just as in the US. In South Africa, Australia and New Zealand, -yse stands alone.
English verbs ending in -lyse or -lyze are not similar to the Greek verb, which is λύω lúō ("I release"). Instead they come from the noun form λύσις lysis with the -ise or -ize suffix. For example, analyse comes from French analyser, formed by haplology from the French analysiser, which would be spelled analysise or analysize in English.
Hart's Rules for Compositors and Readers at the University Press, Oxford states: "In verbs such as analyse, catalyse, paralyse, -lys- is part of the Greek stem (corresponding to the element -lusis) and not a suffix like -ize. The spelling -yze is therefore etymologically incorrect, and must not be used, unless American printing style is being followed."
British and other Commonwealth English uses the ending -logue while American English commonly uses the ending -log for words like analog(ue), catalog(ue), dialog(ue), monolog(ue), homolog(ue), etc. The -gue spelling, as in catalogue, is used in the US, but catalog is more common. Additionally, in American English, dialogue is an extremely common spelling compared to dialog, although both are treated as acceptable ways to spell the word. (thus the inflected forms, cataloged and cataloging vs. catalogued and cataloguing). Words like demagogue, pedagogue, and synagogue are seldom used without -ue even in American English.
In Australia, analog is standard for the adjective, but both analogue and analog are current for the noun; in all other cases the -gue endings strongly prevail, for example monologue, except for such expressions as dialog box in computing, which are also used in the UK. In Australia, analog is used in its technical and electronic sense, as in analog electronics. In Canada and New Zealand, analogue is used, but analog has some currency as a technical term (e.g., in electronics, as in "analog electronics" as opposed to "digital electronics" and some video-game consoles might have an analog stick). The -ue is absent worldwide in related words like analogy, analogous, and analogist.
Both British and American English use the spelling -gue with a silent -ue for certain words that are not part of the -ogue set, such as tongue (cf. tong), plague, vague, and league. In addition, when the -ue is not silent, as in the words argue, ague and segue, all varieties of English use -gue.
In Canada, e is usually preferred over oe and often over ae, but oe and ae are sometimes found in the academic and scientific writing as well as government publications (for example the fee schedule of the Ontario Health Insurance Plan). In Australia, encyclopedia and medieval are spelled with e rather than ae, as with American usage, and the Macquarie Dictionary also notes a growing tendency towards replacing ae and oe with e worldwide. Elsewhere, the British usage prevails, but the spellings with just e are increasingly used. Manoeuvre is the only spelling in Australia, and the most common one in Canada, where maneuver and manoeuver are also sometimes found.
The final consonant of an English word is sometimes doubled in both American and British spelling when adding a suffix beginning with a vowel, for example strip/stripped, which prevents confusion with stripe/striped and shows the difference in pronunciation (see digraph). Generally, this happens only when the word's final syllable is stressed and when it also ends with a lone vowel followed by a lone consonant. In British English, however, a final -l is often doubled even when the final syllable is unstressed. This exception is no longer usual in American English, seemingly because of Noah Webster. The -ll- spellings are nevertheless still deemed acceptable variants by both Merriam-Webster Collegiate and American Heritage dictionaries.
Among consonants other than l, practice varies for some words, such as where the final syllable has secondary stress or an unreduced vowel. In the United States, the spellings kidnaped and worshiped, which were introduced by the Chicago Tribune in the 1920s, are common, but kidnapped and worshipped prevail. Kidnapped and worshipped are the only standard British spellings. However, focused is the predominant spelling in both British and American English, focussed being just a minor variant in British English.
Conversely, there are words where British writers prefer a single l and Americans a double l. In American usage, the spelling of words is usually not changed when they form the main part (not prefix or suffix) of other words, especially in newly formed words and in words whose main part is in common use. Words with this spelling difference include wil(l)ful, skil(l)ful, thral(l)dom, appal(l), fulfil(l), fulfil(l)ment, enrol(l)ment, instal(l)ment. These words have monosyllabic cognates always written with -ll: will, skill, thrall, pall, fill, roll, stall. Cases where a single l nevertheless occurs in both American and British English include null→annul, annulment; till→until (although some prefer til to reflect the single l in until, sometimes using an apostrophe ('til); this should be considered a hypercorrection as till predates the use of until); and others where the connection is not clear or the monosyllabic cognate is not in common use in American English (e.g., null is used mainly as a technical term in law, mathematics, and computer science).
In the UK, a single l is generally preferred in distil(l), instil(l), enrol(l), and enthral(l)ment, and enthral(l), although ll was formerly used; these are always spelled with ll in American usage. The former British spellings instal, fulness, and dulness are now quite rare. The Scottish tolbooth is cognate with tollbooth, but it has a distinct meaning.
In both American and British usages, words normally spelled -ll usually drop the second l when used as prefixes or suffixes, for example full→useful, handful; all→almighty, altogether; well→welfare, welcome; chill→chilblain.
British English sometimes keeps silent "e" when adding suffixes where American English does not. Generally speaking, British English drops it in only some cases in which it is needed to show pronunciation whereas American English only uses it where needed.
Both forms of English keep the silent "e" in the words dyeing, singeing, and swingeing (in the sense of dye, singe, and swinge), to distinguish from dying, singing, swinging (in the sense of die, sing, and swing). In contrast, the verb bathe and the British verb bath both form bathing. Both forms of English vary for tinge and twinge; both prefer cringing, hinging, lunging, syringing.
A "c" is generally soft when followed by an "e", "i", or "y". One word with a pronunciation that is an exception in British English, "sceptic", is spelled "skeptic" in American English. See Miscellaneous spelling differences below.
In the UK, Ireland, Australia, New Zealand and Canada, it is more common to end some past tense verbs with a "t" as in learnt or dreamt rather than learned or dreamed. However, such spellings are also found in American English.
Several verbs have different past tenses or past participles in American and British English:
See also meter/metre, for which there is a British English distinction between these etymologically related forms with different meanings ("meter" being a measuring instrument, for example an ammeter or a water meter) but the standard American spelling is "meter". The spelling used by the International Bureau of Weights and Measures is "metre". This spelling is also the usual one for the unit of length in most English-speaking countries, but only the spelling "meter" is used in American English, and this is officially endorsed by the United States.
In a few cases, essentially the same word has a different spelling that reflects a different pronunciation.
As well as the miscellaneous cases listed in the following table, the past tenses of some irregular verbs differ in both spelling and pronunciation, as with smelt (UK) versus smelled (US) (see American and British English differences: Verb morphology).
|airplane||Aeroplane, originally a French loanword with a different meaning, is the older spelling. The oldest recorded uses of the spelling airplane are British. According to the OED, "[a]irplane became the standard American term (replacing aeroplane) after this was adopted by the National Advisory Committee for Aeronautics in 1916. Although A. Lloyd James recommended its adoption by the BBC in 1928, it has until recently been no more than an occasional form in British English." In the British National Corpus, aeroplane outnumbers airplane by more than 7:1 in the UK. The case is similar for the British aerodrome and American airdrome;Aerodrome is used merely as a technical term in Australia, Canada and New Zealand. The prefixes aero- and air- both mean air, with the first coming from the Ancient Greek word ἀήρ (āēr). Thus, the prefix appears in aeronautics, aerostatics, aerodynamics, aeronautical engineering and so on, while the second occurs invariably in aircraft, airport, airliner, airmail etc. In Canada, airplane is more common than aeroplane, although aeroplane is used as part of the regulatory term "ultra-light aeroplane".|
|aluminium||aluminum||The spelling aluminium is the international standard in the sciences according to the IUPAC recommendations. Humphry Davy, the element's discoverer, first proposed the name alumium, and then later aluminum. The name aluminium was finally adopted to conform with the -ium ending of metallic elements. Canada uses aluminum and Australia and New Zealand aluminium, according to their respective dictionaries and the Canadian trade association is called the 'Aluminium Association of Canada'|
|arse||ass||In vulgar senses "buttocks" ("anus"/"wretch"/"idiot"); unrelated sense "donkey" is ass in both. Arse is very rarely used in the US, though often understood, whereas both are used in British English (with arse being considered vulgar). Arse is also used in Newfoundland.|
|behove||behoove||The 19th century had the spelling behove pronounced to rhyme with move. Subsequently, a pronunciation spelling with doubled oo was adopted in America, while in Britain a spelling pronunciation rhyming with rove was adopted.|
|bogeyman||boogeyman or boogerman||It is pronounced // in the UK, so that the American form, boogeyman //, is reminiscent of musical "boogie" to the British ear. Boogerman // is common in the Southern US and gives an association with the slang term booger for nasal mucus while the mainstream American spelling of boogeyman does not, but aligns more closely with the British meaning where a bogey is also nasal mucus.|
|brent||brant||For the species of goose.|
|carburettor||carburetor||UK: /ˌkɑːbəˈrɛtə/; US: /ˈkɑrbəreɪtər/.|
|charivari||shivaree, charivari||In America, where both terms are mainly regional, charivari is usually pronounced as shivaree, which is also found in Canada and Cornwall, and is a corruption of the French word.|
|eyrie||aerie||This noun (not to be confused with the adjective eerie) rhymes with weary and hairy respectively. Both spellings and pronunciations occur in America.|
|fillet||fillet, filet||Meat or fish. Pronounced the French way (approximately) in the US; Canada follows British pronunciation and distinguishes between fillet, especially as concerns fish, and filet, as concerns certain cuts of beef. McDonald's in the UK and Australia use the US spelling "filet" for their Filet-O-Fish.|
|furore||furor||Furore is a late 18th-century Italian loan-word that replaced the Latinate form in the UK in the following century, and is usually pronounced with a voiced final e. The Canadian usage is the same as the American, and Australia has both.|
|grotty||grody||Clippings of grotesque; both are slang terms from the 1960s.|
|haulier||hauler||Haulage contractor; haulier is the older spelling.|
|jemmy||jimmy||In the sense "crowbar".|
|In America, according to the Merriam-Webster Collegiate Dictionary and The American Heritage Dictionary of the English Language, the British spelling is an also-ran, yet the pronunciation with second-syllable stress is a common variant. In Britain the second syllable is usually stressed.|
|mum(my)||mom(my)||Mother. Mom is sporadically regionally found in the UK (e.g., in West Midlands English). Some British and Irish dialects have mam, and this is often used in Northern English, Hiberno-English, and Welsh English. Scottish English may also use mam, ma, or maw. In the American region of New England, especially in the case of the Boston accent, the British pronunciation of mum is often retained, while it is still spelled mom. In Canada, there are both mom and mum; Canadians often say mum and write mom. In Australia and New Zealand, mum is used. In the sense of a preserved corpse, mummy is always used.|
|naïveté||The American spelling is from French, and American speakers generally approximate the French pronunciation as /( ) /, whereas the British spelling conforms to English norms, as also the pronunciation /( ) /. In the UK, naïveté is a minor variant, used about 20% of the time in the British National Corpus; in America, naivete and naiveté are marginal variants, and naivety is almost unattested.|
|orientated||oriented||In the UK, Australia, and New Zealand, it is common to use orientated (as in family-orientated), whereas in the US, oriented is used exclusively (family-oriented). Both words have the same origins, coming from "orient" or its offshoot "orientation".|
|pyjamas||pajamas||The 'y' represents the pronunciation of the original Urdu "pāy-jāma", and in the 18th century spellings such as "paijamahs" and "peijammahs" appeared: this is reflected in the pronunciation // (with the first syllable rhyming with "pie") offered as an alternative in the first ion of the Oxford English Dictionary. Two spellings are also known from the 18th century, but 'pajama' became more or less confined to the US. Canada follows both British and American usage, with both forms commonplace.|
|pernickety||persnickety||Persnickety is a late 19th-century American alteration of the Scots word pernickety.|
|quin||quint||Abbreviations of quintuplet.|
|In the United States (where the word originated, as scalawag), scallywag is not unknown.|
|sledge||sled||In American usage a sled is smaller and lighter than a sledge and is used only over ice or snow, especially for play by young people, whereas a sledge is used for hauling loads over ice, snow, grass, or rough terrain.|
|speciality||specialty||In British English the standard usage is speciality, but specialty occurs in the field of medicine, and also as a legal term for a contract under seal. In Canada, specialty prevails. In Australia and New Zealand, both are current.|
|titbit||tidbit||According to the Oxford English Dictionary, the oldest form was "tyd bit", and the alteration to "titbit" was probably under the influence of the obsolete word "tit", meaning a small horse or girl.|
In the table below, the main spellings are above the accepted alternative spellings.
|annexe||annex||To annex is the verb in both British and American usage. However, the noun—an annex(e) of a building—the word is spelled with an -e at the end in the UK and Australia, but not in the US and New Zealand.|
|artifact||In British English, artefact is the main spelling and artifact a minor variant. In American English, artifact is the usual spelling. Canadians prefer artifact and Australians artefact, according to their respective dictionaries. Artefact reflects Arte-fact(um), the Latin source.|
|Both the noun and verb. The word comes from Old English æx. In the US, both spellings are acceptable and commonly used. The Oxford English Dictionary states that "the spelling ax is better on every ground, of etymology, phonology, and analogy, than axe, which became prevalent in the 19th century; but it ["ax"] is now disused in Britain".|
|camomile, chamomile||chamomile, camomile||The word derives, via French and Latin, from Greek χαμαίμηλον ("earth apple"). The more common British spelling "camomile", corresponding to the immediate French source, is the older in English, while the spelling "chamomile" more accurately corresponds to the ultimate Latin and Greek source. In the UK, according to the OED, "the spelling cha- is chiefly in pharmacy, after Latin; that with ca- is literary and popular". In the US chamomile dominates in all senses.|
|carat||carat, karat||The spelling with a "k" is used in the US only for the measure of purity of gold. The "c" spelling is universal for weight.|
|cheque||check||In banking. Hence pay cheque and paycheck. Accordingly, the North American term for what is known as a current account or cheque account in the UK is spelled chequing account in Canada and checking account in the US. Some American financial institutions, notably American Express, use cheque, but this is merely a trademarking affectation.|
|chequer||checker||As in chequerboard/checkerboard, chequered/checkered flag etc. In Canada as in the US.|
|The original Mexican Spanish word is chile, itself derived from the Classical Nahuatl chilli. In Merriam-Webster's Collegiate Dictionary, chile and chilli are given as also variants.|
|cosy||cozy||In all senses (adjective, noun, verb).|
|dyke||dike||The spelling with "i" is sometimes found in the UK, but the "y" spelling is rare in the US, where the y distinguishes dike in this sense from dyke, a slang term for a lesbian.|
|doughnut||doughnut, donut||In the US, both are used, with donut indicated as a less common variant of doughnut.|
|draft||British English usually uses draft for all senses as the verb; for a preliminary version of a document; for an order of payment (bank draft), and for military conscription (although this last meaning is not as common as in American English). It uses draught for drink from a cask (draught beer); for animals used for pulling heavy loads (draught horse); for a current of air; for a ship's minimum depth of water to float; and for the game draughts, known as checkers in America. It uses either draught or draft for a plan or sketch (but almost always draughtsman in this sense; a draftsman drafts legal documents).
American English uses draft in all these cases. Canada uses both systems; in Australia, draft is used for technical drawings, is accepted for the "current of air" meaning, and is preferred by professionals in the nautical sense. The pronunciation is always the same for all meanings within a dialect (RP /drɑːft/, General American /dræft/).
|Both spellings have existed since Middle English.|
|gauntlet||gauntlet, gantlet||When meaning "ordeal", in the phrase running the ga(u)ntlet, some American style guides prefer gantlet. This spelling is unused in Britain and less usual in America than gauntlet. The word is an alteration of earlier gantlope by folk etymology with gauntlet ("armoured glove"), always spelled thus.|
|glycerine||glycerin, glycerine||Scientists use the term glycerol, but both spellings are used sporadically in the US.|
|grey||gray||Grey became the established British spelling in the 20th century, pace Dr Johnson and others, and it is but a minor variant in American English, according to dictionaries. Canadians tend to prefer grey. The non-cognate greyhound was never grayhound given that grighund is the origin of the word. Both Grey and Gray are found in proper names everywhere in the English-speaking world. The two spellings are of equal antiquity, and the Oxford English Dictionary states that "each of the current spellings has some analogical support".|
|In the US, "grille" refers to that of an automobile, whereas "grill" refers to a device used for heating food. However, it is not uncommon to see both spellings used in the automotive sense, as well as in Australia and New Zealand. Grill is more common overall in both BrE and AmE.|
|hearken||harken||The word comes from hark. The spelling hearken was probably influenced by hear. Both spellings are found everywhere.|
|idyll||idyl, idyll||Idyl was the spelling of the word preferred in the US by the Merriam-Webster dictionary, for the same reason as the double consonant rule; idyll, the original form from Greek eidullion, is now generally used in both the UK and US.|
|jail||In the UK, gaol and gaoler are used sometimes, apart from literary usage, chiefly to describe a medieval building and guard. Both spellings go back to Middle English: gaol was a loanword from Norman French, while jail was a loanword from central (Parisian) French. In Middle English the two spellings were associated with different pronunciations. In current English the word, however spelled, is always given the pronunciation originally associated only with the jail spelling //. The survival of the gaol spelling in British English is "due to statutory and official tradition".|
|kerb||curb||For the noun designating the edge of a roadway (or the edge of a British pavement/ American sidewalk/ Australian footpath). Curb is the older spelling, and in the UK and US it is still the proper spelling for the verb meaning restrain.|
|(kilo)gram||(Kilo)gramme is used sometimes in the UK but never in the US. (Kilo)gram is the only spelling used by the International Bureau of Weights and Measures.|
|liquorice||licorice||The American spelling is nearer the Old French source licorece, which is ultimately from Greek glykyrrhiza. The British spelling was influenced by the unrelated word liquor. Licorice prevails in Canada and it is common in Australia, but it is rarely found in the UK. Liquorice is all but nonexistent in the US ("Chiefly British", according to dictionaries).|
|mollusc||mollusk, mollusc||The related adjective may be spelled molluscan or molluskan.|
|mould||mold||In all senses of the word. Both spellings have been used since the 16th century. In Canada, both spellings are used. In New Zealand, "mold" refers to a form for casting a shape while "mould" refers to the fungus.|
|The omelet spelling is the older of the two, in spite of the etymology (French omelette). Omelette prevails in Canada and Australia.|
|plough||plow||Both spellings have existed since Middle English. In England, plough became the main spelling in the 18th century. Although plow was Noah Webster's pick, plough continued to have some currency in the US, as the entry in Webster's Third (1961) implies. Newer dictionaries label plough as "chiefly British". The word snowplough/snowplow, originally an Americanism, predates Webster's dictionaries and was first recorded as snow plough. Canada has both plough and plow, although snowplow is more common. In the US, "plough" sometimes describes a horsedrawn kind while "plow" refers to a gasoline (petrol) powered kind.|
|primaeval, primeval||primeval||Primeval is also common in the UK but etymologically 'ae' is nearer the Latin source primus first + aevum age.|
|rack and ruin||wrack and ruin||Several words like "rack" and "wrack" have been conflated, with both spellings thus accepted as variants for senses connected to torture (orig. rack) and ruin (orig. wrack, cf. wreck) In "(w)rack and ruin", the W-less variant is now prevalent in the UK but not the US. The term, however, is rare in the US.|
|skeptic||The American spelling, akin to Greek, is the earliest known spelling in English. It was preferred by Fowler, and is used by many Canadians, where it is the earlier form. Sceptic also pre-dates the European settlement of the US, and it follows the French sceptique and Latin scepticus. In the mid-18th century, Dr Johnson's dictionary listed skeptic without comment or alternative, but this form has never been popular in the UK; sceptic, an equal variant in the old Webster's Third (1961), has now become "chiefly British". Australians generally follow the British usage (with the notable exception of the Australian Skeptics). All of these versions are pronounced with a /k/ (a hard "c"), though in French that letter is silent and the word is pronounced like septique.|
|slew, slue||slue, slew||Meaning "to turn sharply; a sharp turn", the preferred spelling differs. Meaning "a great number" is usually slew in all regions.|
|smoulder||smolder||Both spellings go back to the 16th century, and have existed since Middle English.|
|storey, storeys||story, stories||Level of a building. The letter "e" is used in the UK and Canada to differentiate between levels of buildings and a story as in a literary work. Story is the earlier spelling. The Oxford English Dictionary states that this word is "probably the same word as story [in its meaning of "narrative"] though the development of sense is obscure. One of the first uses of the (now British) spelling "storey" was by Harriet Beecher Stowe in 1852 (Uncle Tom's Cabin xxxii).|
|Sulfur is the preferred spelling by the International Union of Pure and Applied Chemistry (IUPAC) and since 1992 by the UK's Royal Society of Chemistry (RSC). Sulphur is used by British and Irish scientists. However, sulfur has been actively taught in Chemistry in British schools since December 2000. It prevails in Canada and Australia, and it is also found in some American place names (e.g., Sulphur, Louisiana and White Sulphur Springs, West Virginia). American English usage guides suggest sulfur for technical usage, and both sulfur and sulphur in common usage and in literature. The variation between f and ph spellings is also found in the word's ultimate source: Latin sulfur, sulphur.|
|"Thru" is typically used in the US as shorthand. It may be acceptable in informal writing, but for formal documents, "thru" would generally be viewed as "not correct English" and "not a real word". Because "thru" is much shorter than "through", it may also carry a negative connotation, as though the writer of "thru" were "cutting corners" and was "too lazy" to fully spell out "through".
In the COBOL programming language, THRU is accepted as an abbreviation of the keyword THROUGH. Since programmers like to keep their code brief, THRU is generally the preferred form of this keyword.
|tyre||tire||The outer portion of a wheel. In Canada, as in the US, tire is the older spelling, but both were used in the 15th and 16th centuries (for a metal tire). Tire became the settled spelling in the 17th century but tyre was revived in the UK in the 19th century for rubber/pneumatic tyres, possibly because it was used in some patent documents, though many continued to use tire for the iron variety. The Times newspaper was still using tire as late as 1905. For the verb meaning "to grow weary" both American and British English use only the tire spelling.|
|vice||vise, vice||For the two-jawed workbench tool, Americans and Canadians retain the very old distinction between vise (the tool) and vice (the sin, and also the Latin prefix meaning a deputy), both of which are vice in the UK and Australia. Regarding the "sin" and "deputy" senses of vice, all varieties of English use -c-. Thus American English, just as other varieties, has vice admiral, vice president, and vice principal—never vise for any of those.|
|whisky (Scotland), whiskey (Ireland)||whiskey, whisky||In the United States, the whiskey spelling is dominant; whisky is encountered less frequently, but is used on the labels of some major brands (e.g., Early Times, George Dickel, Maker's Mark, and Old Forester) and is used in the relevant US federal regulations. In Canada, whisky is dominant. Often the spelling is selected based on the origin of the product rather than the location of the intended readership, so it may be considered a faux pas to refer to "Scotch whiskey" or "Irish whisky". Both ultimately derive from "uisce beatha" (Irish) and "uisge beatha" (Scottish) meaning 'water of life'.|
|Yoghurt is an also-ran in the US, as is yoghourt in the UK. Although the Oxford Dictionaries have always preferred yogurt, in current British usage yoghurt seems to be prevalent. In Canada, yogurt prevails, despite the Canadian Oxford preferring yogourt, which has the advantage of satisfying bilingual (English and French) packaging requirements. Australian usage tends to follow the UK. Whatever the spelling is, the word has different pronunciations: // in the UK, // in New Zealand, America, Ireland, and Australia. The word comes from the Turkish language word yoğurt. The voiced velar fricative represented by ğ in the modern Turkish (Latinic) alphabet was traditionally written gh in Latin script of the Ottoman Turkish (Arabic) alphabet used before 1928.|
British English often prefers hyphenated compounds, such as anti-smoking, whereas American English discourages the use of hyphens in compounds where there is no compelling reason, so antismoking is much more common. Many dictionaries do not point out such differences. Canadian and Australian usage is mixed, although Commonwealth writers generally hyphenate compounds of the form noun plus phrase (such as or-in-chief). Commander-in-chief prevails in all forms of English.
Compound verbs in British English are hyphenated more often than in American English.
Acronyms pronounced as words are often written in title case by Commonwealth writers, but usually as upper case by Americans: for example, Nasa / NASA or Unicef / UNICEF. This does not apply to abbreviations that are pronounced as individual letters (referred to by some as "initialisms"), such as US, IBM, or PRC (the People's Republic of China), which are virtually always written as upper case. However, sometimes title case is still used in the UK, such as Pc (Police Constable).
Contractions where the final letter is present are often written in British English without full stops/periods (Mr, Mrs, Dr, St, Ave). Abbreviations where the final letter is not present generally do take full stops/periods (such as vol., etc., i.e., ed.); British English shares this convention with the French: Mlle, Mme, Dr, Ste, but M. for Monsieur. In American and Canadian English, abbreviations like St., Ave., Mr., Mrs., Ms., Dr., and Jr., usually require full stops/periods. Some initials are usually upper case in the US but lower case in the UK: liter/litre and its compounds (2 L or 25 mL vs 2 l or 25 ml); and ante meridiem and post meridiem (10 P.M. or 10 PM vs 10 p.m. or 10 pm). Both AM/PM and a.m./p.m. are acceptable in American English, but U.S. style guides overwhelmingly prefer a.m./p.m.
The use of quotation marks, also called inverted commas or speech marks, is complicated by the fact that there are two kinds: single quotation marks (') and double quotation marks ("). British usage, at one stage in the recent past, preferred single quotation marks for ordinary use, but double quotation marks are again now increasingly common; American usage has always preferred double quotation marks, as have Canadian, Australian, and New Zealand English. It is the practice to alternate the type of quotation marks used where there is a quotation within a quotation.
The convention used to be, and in American English still is, to put full stops (periods) and commas inside the quotation marks, irrespective of the sense. British English has moved away from this style while American English has kept it. British style now prefers to punctuate according to the sense, in which punctuation marks only appear inside quotation marks if they were there in the original. Formal British English practice requires a full stop to be put inside the quotation marks if the quoted item is a full sentence that ends where the main sentence ends, but it is common to see the stop outside the ending quotation marks.
Johnson's dictionary became the accepted standard for private spelling ... of a literate Englishman ... during the nineteenth century ... Webster had more success in influencing the development of American usage than Johnson had with British usage.
not an error...simply an Americanism
may be legitimately spelled with either -ize or -ise throughout the English-speaking world (except in America, where -ize is always used).
although both l and L are internationally accepted symbols for the liter, to avoid this risk the preferred symbol for use in the United States is L
Use, read and write standard metric units (km, m, cm, mm, kg, g, l, ml), including their abbreviations
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