preposition

n. Gram. Word governing (and usu. Preceding) a noun or pronoun and expressing a relation to another word, as in: the man on the platform, came after dinner, went by train.  prepositional adj. [latin praepono -posit- place before]

n. 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.