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.