black jack

1. (countable, uncountable)Any of certain species of Caranx of gamefish, including C. latus and C. crysos, but especially Caranx lugubris.

2. (countable, uncountable)Certain beggarticks (Bidens spp.), especially Bidens pilosa.

3. (countable, uncountable)Sphalerite.

4. (countable, uncountable)A tufted or ring-necked scaup duck (Aythya collaris).

5. (countable, uncountable)Used other than figuratively or idiomatically: see black, jack.

6. (countable, obsolete, uncountable)Larva of a turnip sawfly (Athalia rosae)

regular