black-jack

plural black-jacks

1. UKobsoleteuncountablechemistrySphalerite; zincblende.
2. obsoleteuncountableCaramel or burnt sugar, used to colour wines, spirits, ground coffee, etc.
3. countableobsoleteuncountableA large leather vessel for beer, etc.

   ‘Oh yes, we’ll probably be wolfing down pasty jambics and swigging away at great black jacks of swingeing ale in no time now,’ he went on heartly.

   1936, Norman Lindsay, The Flyaway Highway, Sydney: Angus and Robertson, page 35

4. countableobsoleteuncountableA water oak or barren oak (Quercus nigra).
5. countableobsoleteuncountablecirca 1700sA native African longshoreman or sailor working on a boat.
6. countableuncountableA coalfish (Pollachius virens).
7. countableuncountableA larva of a sawfly of species Athalia rosae (syns. Athalia centifolia, A. spinarum).
8. alternativecountableuncountableAlternative form of blackjack.