Black"-jack`, n.
1. Min.
A name given by English miners to sphalerite, or zinc blende; -- called also false galena. See Blende.
2.
Caramel or burnt sugar, used to color wines, spirits, ground coffee, etc.
3.
A large leather vessel for beer, etc.
[Obs.]
4. Bot.
The Quercus nigra, or barren oak.
5.
The ensign of a pirate.
© Webster 1913.