1540s, from M.E. bught, probably from an unrecorded O.E. variant of byht "a bend," from P.Gmc. *bukhta-. Sense evolved from "a circuit of any kind" (as of a plow) to "a round at any kind of exercise" (1570s), "a round at fighting" (1590s), "a fit of drinking" (1660s).