| blackjack oak n. A deciduous oak tree (Quercus marilandica) native mostly to the southeastern United States and having blackish bark and leaves with three shallow lobes at the widened apex. |
| blackjack oak | |
noun | |
| 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 |