1.
Often Jack Informal. A man; a fellow.
2.
a. One who does odd or heavy jobs; a laborer. b. One who works in a specified manual trade. Often used in combination: a lumberjack; a steeplejack. c. Jack A sailor; a tar.
3. Abbr. J Games. A playing card showing the figure of a servant or soldier and ranking below a queen. Also called knave.
4. Games. a. jacks
(used with a sing. or pl. verb) A game played with a set of small six-pointed metal pieces and a small ball, the object being to pick up the pieces in various combinations. b. One of the metal pieces so used.
5. Sports. A pin used in some games of bowling.
6. a. A usually portable device for raising heavy objects by means of force applied with a lever, screw, or hydraulic press. b. A wooden wedge for cleaving rock.
7. Nautical. a. A support or brace, especially the iron crosstree on a topgallant masthead. b. A small flag flown at the bow of a ship, usually to indicate nationality.
8. The male of certain animals, especially the ass.
9. Any of several food and game fishes of the family Carangidae, found in tropical and temperate seas.
10. A jackrabbit.
11. A socket that accepts a plug at one end and attaches to electric circuitry at the other.
12. Slang. Money.
13. Applejack.
To hunt or fish for quarry by using a jacklight.
To masturbate.