"Rocky Mountain sheep," 1805, American English (Lewis & Clark), from big + horn (n.).
Entries linking to bighorn
big adj.
c. 1300, at first found chiefly in writings from northern England and north Midlands, with a sense of "powerful, strong;" a word of obscure origin. It is possibly from a Scandinavian source (compare Norwegian dialectal bugge "great man"). Old English used micel (see much) in many of the same senses.
Big came into general use c. 1400. The meaning "of great size" is from late 14c., as is that of "full-grown, grown up." The sense of "important, influential, powerful" is from c. 1400. The meaning "haughty, inflated with pride" is from 1570s. The sense of "generous" is U.S. colloquial by 1913.
Big band as a musical style is from 1926. Slang big head "conceit" is recorded by 1850. Big business "large commercial firms collectively" is from 1913 (before that it meant "a profitable income in business"). Big top "main tent of a circus" is from 1895. Big game "large animals hunted for sport" is from 1864. Big house "penitentiary" is U.S. underworld slang is attested by 1915 (in London, "a workhouse," 1851). In financial journalism, big ticket items were so called from 1956. Big lie is from Hitler's grosse Lüge.
horn n.
Old English horn "horn of an animal; projection, pinnacle," also "wind instrument" (originally one made from animal horns), from Proto-Germanic *hurni- (source also of German Horn, Dutch horen, Old Frisian horn, Gothic haurn), from PIE root *ker- (1) "horn; head."
Late 14c. as "one of the tips of the crescent moon." The name was retained for a of musical instruments that developed from the hunting horn; the French horn is the true representative of the class. Of dilemmas from 1540s; of automobile warning signals from 1901. Slang meaning "erect penis" is suggested by c. 1600. Jazz slang sense of "trumpet" is by 1921. Meaning "telephone" is by 1945. Figurative senses of Latin cornu included "salient point, chief argument; wing, flank; power, courage, strength." Horn of plenty is from 1580s. To make horns at "hold up the fist with the two exterior fingers extended" as a gesture of insult is from c.1600.
Symbolic of cuckoldry since mid-15c. (the victim was fancied to grow one on his head). The image is widespread in Europe and perhaps as old as ancient Greece. The German linguist Hermann Dunger ('Hörner Aufsetzen' und 'Hahnrei', "Germania" 29, 1884) ascribes it to a custom surviving into 19c., "the old practice of engrafting the spurs of a castrated cock on the root of the excised comb, which caused them to grow like horns" [James Hastings, "Encyclopedia of Religion and Ethics"] but the image could have grown as well from a general gesture of contempt or insult made to wronged husbands, "who have been the subject of popular jest in all ages" [Hastings].