Definition of "blackjack oak" []

• 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. (noun)

American Heritage(R) Dictionary of the English Language, Fifth Edition. Copyright (c) 2011 by Houghton Mifflin Harcourt Publishing Company. Published by Houghton Mifflin Harcourt Publishing Company. All rights reserved.