"female of a bovine animal," especially the domestic ox, Middle English cu, qu, kowh, from Old English cu "cow," from Proto-Germanic *kwon (source also of Old Frisian ku, Middle Dutch coe, Dutch koe, Old High German kuo, German Kuh, Old Norse kyr, Danish, Swedish ko), earlier *kwom, from PIE root *gwou- "ox, bull, cow."
Applied to the females of various large animals from late 14c. As an insulting or degrading word for a woman, 1690s.
"intimidate, daunt the fear or courage of," c. 1600, probably [OED] from Old Norse kuga "oppress," which is of unknown origin but perhaps has something to do with the Scandinavian forms of cow (n.) on the notion of "easily herded." Related: Cowed; cowing.
"heifer, young cow that has not had a calf," Scottish and Northern English dialect, late 14c. (c. 1300 in surnames), quie, from Old Norse kviga, apparently from ku "cow" (compare Danish kvie; see cow (n.)).
1809, "bell attached to the neck of a cow to indicate her whereabouts" (usually oblong and of a heavy, clanking tone), from cow (n.) + bell (n.). They are cut from sheet metal (mostly copper, or iron coated with bronze) and folded into shape. As a musical instrument (without the clapper) by 1919; in that period associated with, and scorned as an absurdity of, jazz.
Art is long and time is fleeting,
And the man who cannot play,
On a cowbell wildly beating,
Calls it "jazz"—and gets away.
[from "The Psalm of Jazz," Oregon Voter, Aug. 30, 1919]
But an article on cowbells in "Hardware" magazine for Dec. 25, 1897, notes: "Cowbells are made in ten sizes, whose sounds range through an octave. Sometimes musical entertainers who play upon bells of one sort and another come to the manufacturer, and by selection among bells of the various sizes find eight bells that are accurate in scale."
American-English sense of "man employed to have care of grazing cattle on the Great Plains for a stockman or ranch, doing his work on horseback" is by 1849. Earlier it was an insulting name for a band of marauding loyalists in the neighborhood of New York during the Revolution (1775). In figurative use by 1942 for "brash and reckless young man" (as an adjective meaning "reckless," from 1920s).
The oldest word for "one whose occupation is the care of cattle" is cowherd (late Old English). Cowhand is first attested 1852 in American English (see hand (n.)). Cowpoke (said to be 1881, not in popular use until 1940s) was said to be originally restricted to those who prodded cattle onto railroad cars with long poles. Cowboys and Indians as a children's game (imitating movie serials, etc.) is by 1941.