preposition Meaning, Definition & Usage

  1. noun a function word that combines with a noun or pronoun or noun phrase to form a prepositional phrase that can have an adverbial or adjectival relation to some other word
  2. noun (linguistics) the placing of one linguistic element before another (as placing a modifier before the word it modifies in a sentence or placing an affix before the base to which it is attached)

WordNet

Prep`o*si"tion noun
Etymology
L. praepositio, fr. praeponere to place before; prae before + ponere to put, place: cf. F. préposition. See Position, and cf. Provost.
Definitions
  1. (Gram.) A word employed to connect a 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; -- so called because usually placed before the word with which it is phrased; as, a bridge of iron; he comes from town; it is good for food; he escaped by running.
  2. A proposition; an exposition; a discourse. Obs.
    He made a long preposition and oration. Fabyan.

Webster 1913