Meaning

noun something added to another thing but not an essential part of it

noun a person who is an assistant or subordinate to another

noun a construction that can be used to extend the meaning of a word or phrase but is not one of the main constituents of a sentence

originFrom Latin adiunctus, perfect passive participle of adiungō (“join to”), from ad + iungō (“join”). Doublet of adjoint.

Etymology from Wiktionary, CC BY-SA 3.0