beau (n.)

"attendant suitor of a lady," 1720, from French beau "the beautiful," noun use of an adjective, from Old French bel "beautiful, handsome, fair, genuine, real" (11c.), from Latin bellus "handsome, fine, pretty, agreeable" (see belle). Meaning "man who attends excessively to dress, etiquette, etc.; a fop; a dandy" is from 1680s, short for French beau garçon "pretty boy" (1660s). Plural is beaus or beaux. Beau Brummel, arbiter of men's fashion in Regency London, was George B. Brummel, gentleman (1778-1840).