The part of speech is the term used to describe how a particular word is used. In English there are eight ways a word can be used--there are eight parts of speech.
1. Nouns name anything.
2. Verbs express action or state of being.
3. Pronouns replace nouns.
4. Adjectives modify nouns or pronouns.
5. Adverbs modify verbs, adjectives, or other adverbs.
6. Prepositions show the relationship between a noun or
pronoun and another word in the sentence.
7. Conjunctions connect words and sentence parts.
8. Interjections express strong feeling.
For more specific details on the individual parts of speech, see the specific entry for each part of speech.