Found one definition

  1.                 From GNU Collaborative International Dictionary of English, version 0.54:
                    

    Post, n. [F. poste, LL. posta station, post (where horses were kept), properly, a fixed or set place, fem. fr. L. positus placed, p. p. of ponere. See {Position}, and cf. {Post} a pillar.]

    1. The place at which anything is stopped, placed, or fixed; a station. Specifically: (a) A station, or one of a series of stations, established for the refreshment and accommodation of travelers on some recognized route; as, “a stage or railway post”. (b) A military station; the place at which a soldier or a body of troops is stationed; also, the troops at such a station. (c) The piece of ground to which a sentinel's walk is limited.

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    2. A messenger who goes from station; an express; especially, one who is employed by the government to carry letters and parcels regularly from one place to another; a letter carrier; a postman.

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    In certain places there be always fresh posts, to carry that further which is brought unto them by the other.

    -- Abp. Abbot.

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    I fear my Julia would not deign my lines, Receiving them from such a worthless post.

    -- Shak.

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    3. An established conveyance for letters from one place or station to another; especially, the governmental system in any country for carrying and distributing letters and parcels; the post office; the mail; hence, the carriage by which the mail is transported.

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    I send you the fair copy of the poem on dullness, which I should not care to hazard by the common post.

    -- Pope.

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    4. Haste or speed, like that of a messenger or mail carrier. [Obs.] “In post he came.”

    Shak.

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    5. One who has charge of a station, especially of a postal station. [Obs.]

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    He held office of postmaster, or, as it was then called, post, for several years.

    -- Palfrey.

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    6. A station, office, or position of service, trust, or emolument; as, “the post of duty; the post of danger.”

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    The post of honor is a private station.

    -- Addison.

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    7. A size of printing and writing paper. See the Table under {Paper}.

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    Post and pair, an old game at cards, in which each player a hand of three cards. B. Jonson. -- Post bag, a mail bag. -- Post bill, a bill of letters mailed by a postmaster. -- Post chaise, or Post coach, a carriage usually with four wheels, for the conveyance of travelers who travel post. -- Post day, a day on which the mall arrives or departs. -- Post hackney, a hired post horse. Sir H. Wotton. -- Post horn, a horn, or trumpet, carried and blown by a carrier of the public mail, or by a coachman. -- Post horse, a horse stationed, intended, or used for the post. -- Post hour, hour for posting letters. Dickens. -- Post office. (a) An office under governmental superintendence, where letters, papers, and other mailable matter, are received and distributed; a place appointed for attending to all business connected with the mail. (b) The governmental system for forwarding mail matter. -- Postoffice order. See {Money order}, under {Money}. -- Post road, or Post route, a road or way over which the mail is carried. -- Post town. (a) A town in which post horses are kept. (b) A town in which a post office is established by law. -- To ride post, to ride, as a carrier of dispatches, from place to place; hence, to ride rapidly, with as little delay as possible. -- To travel post, to travel, as a post does, by relays of horses, or by keeping one carriage to which fresh horses are attached at each stopping place.

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