1. often Jack Informal A man; a fellow.
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.
a. jacks (used with a sing. or pl. verb) A game played with a set of small, six-pointed, traditionally metal pieces and a small ball, the object being to pick up the pieces in various combinations.
b. One of the six-pointed pieces so used.
5. Sports A pin used in some games of bowling.
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. A device used for turning a spit.
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.
9. The male of certain animals, especially the ass.
10. Any of various food and game fishes of the family Carangidae, found in tropical and temperate seas.
11. A jackrabbit.
12. A socket that accepts a plug at one end and attaches to electric circuitry at the other.
13. Slang Money.
15. Slang A small or worthless amount: You don't know jack about that.
v. jacked, jack·ing, jacks
1. To hunt or fish for with a jacklight: hunters illegally jacking deer.
a. To move or hoist by using a jack. Often used with up: jacked the rear of the car to replace the tire.
b. To raise (something) to a higher level, as in cost. Often used with up: "Foreign producers jacked up the price on some steels by over 100%" (Forbes).
3. Baseball To hit (a pitched ball) hard, especially for a home run.
a. To steal: Someone jacked my bike.
b. To rob or cheat: The dealer jacked me on the price.
1. To hunt or fish by using a jacklight.
2. To plug into an electronic device by means of a jack.
1. To spend time idly.
2. To toy, tinker, or mess: He's been jacking around with that motor for days.
3. To take unfair advantage of, deceive, or manipulate.
jack off Vulgar Slang
1. To masturbate. Usually used of a man.
2. To bring (someone) to orgasm.
To excite emotionally.
[From the name Jack, from Middle English Jakke, possibly from Old French Jacques, from Late Latin Iacōbus; see JACOB. N., sense 15, short for JACK SHIT. V. tr., senses 4a and b, short for HIJACK.]
(click for a larger image)jack
The American Heritage® Dictionary of the English Language, Fifth Edition copyright ©2016 by Houghton Mifflin Harcourt Publishing Company. All rights reserved.
The American Heritage Dictionary Blog
Check out our blog, updated regularly, for new words and revised definitions, interesting images from the 5th edition, discussions of usage, and more.
American Heritage Dictionary Products
The American Heritage Dictionary, 5th Edition
The American Heritage Dictionary of Idioms
The American Heritage Roget's Thesaurus
Curious George's Dictionary
The American Heritage Children's Dictionary
The American Heritage Dictionary of Indo-European Roots
The American Heritage Student Grammar Dictionary
The American Heritage Desk Dictionary + Thesaurus
The American Heritage Science Dictionary
The American Heritage Dictionary of Business Terms
The American Heritage Student Dictionary
The American Heritage Essential Student Thesaurus