PREPOSI'TION, noun s as z. [Latin proepositio, proepono, proepositus; proe and pono, to put.] In grammar, a word usually put before another to express some relation or quality, action or motion to or from the thing specified; as medicines salutary to health; music agreeable to the ear; virtue is valued for its excellence; a man is riding to Oxford from London. Prepositions govern cases of nouns, and in English are sometimes placed after the word governed; as, which person do you speak to? for, to which person do you speak? This separation of the preposition from the governed word is sometimes allowable in colloquial use, but is generally inelegant.