Pronunciation: - ˌ jak
Function: noun
Date: 1591
1 [ black + jack (vessel)] : a tankard for beer or ale usually of tar-coated leather
2 : SPHALERITE
3 : a hand weapon typically consisting of a piece of leather-enclosed metal with a strap or springy shaft for a handle
4 : an often scrubby oak ( Quercus marilandica ) chiefly of the southeastern U.S. ― called also blackjack oak
5 : a card game the object of which is to be dealt cards having a higher count than those of the dealer up to but not exceeding 21 ― called also twenty-one vingt-et-un