Cowboy \Cow"boy`\ (-boi`), n.

1. A cattle herder; a drover; specifically, one of an adventurous class of herders and drovers on the plains of the Western and Southwestern United States.

2. One of the marauders who, in the Revolutionary War infested the neutral ground between the American and British lines, and committed depredations on the Americans.

Source: Webster's Revised Unabridged Dictionary (1913)