Informed guesswork on how the word “atonement” came to have the meaning it has today.
In The Church of Jesus Christ of Latter-Day Saints the word “atonement” has a very specific meaning: it is the thing Jesus Christ did to make possible the remission of our sins. But when you think about it, that’s a rather odd concept to have its own English word. Until around a.d. 1600 that concept wouldn’t have been discussed much in English as the liturgy and scripture were in Latin prior to that. So how did this meaning become so fixed?
Here’s what I was able to find in etymology dictionaries. The word “atone” first appears in written English in the mid 16th century as a contraction of the 12th century adverbial phrase “at onen”, or in modern English “in one”, a parallel construction of the Latin “adunare” (a spork is a spoon and a fork adunare). At some point it shifted from an adverb to a verb, something closer to “merge” or “unite”.
So why, then, does the bible use the word “atonement” as it does? Exodus chapters 29 and 30 are the first to use the phrase when discussing the annual “sin offering of atonement” and “atonement money” “to make an atonement for your souls”. In exodus 32 Moses suggests he might be able to “make an atonement for your sin” of worshiping the golden calf. In Leviticus the word appears in almost every chapter, speaking of sacrifices that make an atonement for sins, people, the tabernacle, etc. Thereafter it shows up only rarely in the Old Testament (Numbers, 2 Samuel, both Chronicles, Nehemiah) always referring back to the sacrifices of atonement.
The wording in these passages is a bit vague, particularly when you insert the word “unity” or “unification” in place of “atonement”. The common reading is that people need to be reunited with God, and that these sacrifices are a symbolic act to provide that unity. Another reading is that the soul is fractured by sin, or even fractured in its initial state, and the atonement is a (re)unification of the soul itself. Another interpretation is that the people become scattered with sin and atonement makes them again, “one people under God”.
The New Testament uses the word “atone” only once, in the Epistle of Paul to the Romans, chapter 5 verse 11: “Jesus Christ, by whom we have now received the atonement”. This, I suspect, is where the usage of atonement as “that thing Christ did for us” originates, for the context here makes any literal reading of at onen rather difficult. It is my guess that, as the New Testament became the most read book in English and as “unity” replaced “atone” in spoken English, Romans 5:11 was used to allocate to the now-unused word “atone” this new and important idea that encapsulates Christianity.
Of course, this was not the only candidate word for that idea. “Crucify” (from the Latin crux figere, “fasten to a cross”), while not really unused, was close enough to it to take the same meaning. Sometimes “salvation” or “redemption” are used, but they also have independent living-English definitions so they aren’t as serviceable.
But all of this begs the question, why can’t we just take the word from an older tongue as we did with other religious concepts such as “Messiah” and “sin”? Part of the difficulty comes, I think, in a cultural difference.
From my reading of Hebrew texts, the Hebrews where not particularly fixed on having things neatly packaged and labeled with words. Much of the prophets writings in the Old Testament deal with “the atonement”, but “the divine way in which He can take our whipping for us” or “the act in which He engraved us on his palms so that he can forgive more fault in us than any husband or mother can forgive in a wife or child” are both too long for Helenistic verbiage and too brief to capture the poetry of the Old Testament language.
So, if not Hebrew, why not Latin? I really don’t know, but I suspect it has to do with the dying nature of the Roman empire by the time Christianity was popularized, with the corruption of doctrine in the early church, with the dependence of Rome on Greece for its reason and intellectualism, and the lack of a single word in the scriptural texts being translated.
This leaves then one question, which is why the LDS people have fixated on “atonement” when many other Christian sects have gravitated toward “crucifixion” instead. I suspect this is the result of the translation of the Book of Mormon into English occurring at a time when “atonement” was in vogue. The Nephite people, possibly due to the surprisingly logical character of Nephi himself, have a more Helenistic word-label approach to divine truth than do the Eastern Hebrews, and some glyph in their hieroglyphs was used to refer to “that thing Christ does”. When translated into early 19th century American English, that glyph became “atonement”, forever fixing in LDS vernacular the use of “atonement” rather than “crucifixion” for “Christ’s great deed”.
It should be reiterated that the above is mostly speculation. I will be neither surprised nor disappointed when I learn it is wrong.