What is the meaning of Preposition?

Any of a class of non-inflecting words typically employed to connect a following noun or a pronoun, in an adjectival or adverbial sense, with some other word: a particle used with a noun or pronoun (in English always in the objective case) to make a phrase limiting some other word.

An adposition.

A proposition; an exposition; a discourse.

To place in a location before some other event occurs.

genitive singular of prepositio

A word that is used in conjunction with a noun or pronoun in order to form a phrase.

a preposition (part of speech)

Source: wiktionary.org