Definify.com
Webster 1913 Edition
Black-jack
Black′-jackˊ
,Noun.
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.