| blackjack | (n) a piece of metal covered by leather with a flexible handle; used for hitting people, Syn. cosh, sap |
| blackjack | (n) a gambling game using cards; the object is to hold cards having a higher count than those dealt to the banker up to but not exceeding 21, Syn. twenty-one, vingt-et-un |
| blackjack oak | (n) a common scrubby deciduous tree of central and southeastern United States having dark bark and broad three-lobed (club-shaped) leaves; tends to form dense thickets, Syn. Quercus marilandica, jack oak, blackjack |
| black flag | (n) a flag usually bearing a white skull and crossbones on a black background; indicates a pirate ship, Syn. blackjack, pirate flag, Jolly Roger |
| blackmail | (v) exert pressure on someone through threats, Syn. pressure, blackjack |
