post horn

Century Dictionary and Cyclopedia

1. n. A postman's horn; a horn blown by the driver or guard of a mail-coach, and at present used on four-in-hands for pleasure driving. It is a straight tube of brass or copper, from two to four feet long, the bore gradually enlarging downward, with a small, shallow, cupped mouthpiece. Its pitch varies with its length. It is occasionally used as a musical instrument by exceptional players.
2. n. Same as bugle, 1.
3. n. A musical phrase or call, such as is given by a post-horn or bugle.

Wiktionary

1. n. historical A type of brass horn used to signal the arrival or departure of a post rider or mail coach.
2. n. music A valveless musical instrument based on such a horn, used in orchestral music.

GNU Webster's 1913

1. n. a horn, or trumpet, carried and blown by a carrier of the public mail, or by a coachman.

WordNet 3.0

1. n. wind instrument used by postilions of the 18th and 19th centuries