apposition (Noun) — A grammatical relation between a word and a noun phrase that follows. ex. "'Rudolph the red-nosed reindeer' is an example of apposition"
apposition (Noun) — (biology) growth in the thickness of a cell wall by the deposit of successive layers of material.
apposition (Noun) — The act of positioning close together (or side by side). ex. "it is the result of the apposition of contrasting colours"