bronco n |ˈbrɑŋko| Also sp broncho; abbr bronc(h) [ bronco adj] orig West, now widespread

A wild, unbroken, or vicious horse; now esp a bucking horse used in rodeo competitions.

1861 Sacramento Daily Union (CA) 28 Nov 1/7, One rickety cart, one harrow, and we don’t know positively but a yoke of “Broncos,” . . is to be transferred to the Tule River Reservation. 1869 McClure 3000 Miles 148 WY, At Millersville, twelve miles from Bridger, they hitch up six raw bronchos (wild California horses). 1879 Bishop Lady’s Life Rocky Mts. 193 CO, My “mad, bad broncho,” on which I had been travelling for a fortnight, cantered lightly over the snow. 1888 (1896) Roosevelt Ranch Life & Hunting-Trail 108 ND, “I could n’t stand that,” said the narrator, “so I just told him I reckoned I knew where his own lost horses were, and I saddled up my bronch’ and piloted him to them.” 1910 Raine Bucky O’Connor 94 SW, You’re going to . . learn to stick to your saddle when the bronc and you disagrees. 1937 Sandoz Slogum 275 NE (as of 1900–20), Several times he tried to speak . . a friendly word, about ordinary things, like . . a coyotey team of bronchs hitched to an old top buggy they passed. 1944 Natl. Geogr. Mag. 85.656/1 ID, But the greatest fun is the rodeo—a real Wild West spectacle in which hard-working ranch cowboys ride unbroken broncos and steers fresh from the ranges. 1948 Range Riders Western May 30/2 (DA), Two tired broncs stamped their hoofs restlessly. c1960 Wilson Coll. csKY, Broncho. . . A wild horse, a very late word in the region; also bucking broncho. 1965–70 DARE (Qu. K42, A horse that is rough, wild, or dangerous) 178 Infs, widespread, Bronco. 1980 Wilson Daily Times (NC) 27 Oct Sec II 1/4, He said he didn’t compete in the bucking bronco or bullriding contests—he got enough opportunities at bucking broncos while breaking horses and training them. 1989 Chron.–Telegram (Elyria OH) 27 Jan 1/2, The 31-year-old Avon Lake resident is the only female bronc rider in the country. 2015 Navajo Times (Window Rock AZ) 18 June sec B 2/5, Kaye grew up in a rodeo family. His father was a bull rider and bronc rider.