jack

¹ American  

[jak] / dʒæk /

noun

1. any of various portable devices for raising or lifting heavy objects short heights, using various mechanical, pneumatic, or hydraulic methods.

2. Also called knave.  Cards. a playing card bearing the picture of a soldier or servant.

3. Electricity. a connecting device in an electrical circuit designed for the insertion of a plug.

4. Informal. Jack, fellow; buddy; man (usually used in addressing a stranger).

   Hey, Jack, which way to Jersey?

5. Also called jackstone.  Games.

   1. one of a set of small metal objects having six prongs, used in the game of jacks.

   2. one of any other set of objects, as pebbles, stones, etc., used in the game of jacks.

   3. (used with a singular verb) jacks, a children's game in which small metal objects, stones, pebbles, or the like, are tossed, caught, and moved on the ground in a number of prescribed ways, usually while bouncing a rubber ball.

6. any of several carangid fishes, especially of the genus Caranx, as C. hippos crevalle jack, or jack crevalle, of the western Atlantic Ocean.

7. Slang. money.

   He won a lot of jack at the races.

8. Slang: Vulgar. jack shit.

9. Nautical.

   1. a small flag flown at the jack staff of a ship, bearing a distinctive design usually symbolizing the nationality of the vessel.

   2. Also called jack crosstree.  either of a pair of crosstrees at the head of a topgallant mast, used to hold royal shrouds away from the mast.

10. Jack, a sailor.

11. lumberjack.

12. applejack.

13. jack rabbit.

14. jackass.

15. jacklight.

16. a device for turning a spit.

17. a small wooden rod in the mechanism of a harpsichord, spinet, or virginal that rises when the key is depressed and causes the attached plectrum to strike the string.

18. Lawn Bowling. a small, usually white bowl or ball used as a mark for the bowlers to aim at.

19. Also called clock jack.  Horology. a mechanical figure that strikes a clock bell.

20. a premigratory young male salmon.

21. Theater. brace jack.

22. Falconry. the male of a kestrel, hobby, or especially of a merlin.

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verb (used with object)

1. to lift or move (something) with or as if with a jack (usually followed byup ).

   to jack a car up to change a flat tire.

2. Informal. to increase, raise, or accelerate (prices, wages, speed, etc.) (usually followed byup ).

3. Informal. to boost the morale of; encourage (usually followed byup ).

4. Slang. to mess up, ruin, or injure (usually followed byup ): I jacked my shoulder when I fell.

   The paint job was all jacked up.

   I jacked my shoulder when I fell.

5. to jacklight.

verb (used without object)

1. to jacklight.

adjective

1. Carpentry. having a height or length less than that of most of the others in a structure; cripple.

   jack rafter; jack truss.

verb phrase

1. jack up to give oneself an injection of a controlled substance.

   After 30 heroin-free days, he was let out for the afternoon and came straight to my door, begging to jack up.

2. jack off to masturbate.

idioms

1. every man jack, everyone without exception.

   They presented a formidable opposition, every man jack of them.

jack ² American  

[jak] / dʒæk /

verb (used with object)

Slang.

1. to steal: Hackers jacked my email account in a phishing scam.

   Some neighborhood kids jacked her car and took it for a joyride.

   Hackers jacked my email account in a phishing scam.

2. to rob.

   He got jacked on his way home from the club.

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jack ³ American  

[jak] / dʒæk /

noun

1. jackfruit.

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jack ⁴ American  

[jak] / dʒæk /

noun

1. a defensive coat, usually of leather, worn in medieval times by foot soldiers and others.

2. a container for liquor, originally of waxed leather coated with tar.

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Jack ⁵ American  

[jak] / dʒæk /

noun

1. a male given name, form of Jacob or John.

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jack ¹ British  

/ dʒæk /

noun

1. a man or fellow

2. a sailor

3. the male of certain animals, esp of the ass or donkey

4. a mechanical or hydraulic device for exerting a large force, esp to raise a heavy weight such as a motor vehicle

5. any of several mechanical devices that replace manpower, such as a contrivance for rotating meat on a spit

6. one of four playing cards in a pack, one for each suit, bearing the picture of a young prince; knave

7. bowls a small usually white bowl at which the players aim with their own bowls

8. electrical engineering a female socket with two or more terminals designed to receive a male plug ( jack plug ) that either makes or breaks the circuit or circuits

9. a flag, esp a small flag flown at the bow of a ship indicating the ship's nationality Compare Union Jack

10. nautical either of a pair of crosstrees at the head of a topgallant mast used as standoffs for the royal shrouds

11. a part of the action of a harpsichord, consisting of a fork-shaped device on the end of a pivoted lever on which a plectrum is mounted

12. any of various tropical and subtropical carangid fishes, esp those of the genus Caranx, such as C. hippos ( crevalle jack )

13. Also called: jackstone.  one of the pieces used in the game of jacks

14. short for applejack bootjack jackass jackfish jack rabbit lumberjack

15. a slang word for money

16. everyone without exception

17. slang venereal disease

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adjective

1. slang tired or fed up with (something)

verb

1. to lift or push (an object) with a jack

2. electrical engineering to connect (an electronic device) with another by means of a jack and a jack plug

3. Also: jacklight.  to hunt (fish or game) by seeking them out or dazzling them with a flashlight

Jack ² British  

/ dʒæk /

noun

1. informal

   1. a remark indicating smug and complacent selfishness

   2. ( as modifier )

      an ``I'm all right, Jack'' attitude

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jack ³ British  

/ dʒæk /

noun

1. a short sleeveless coat of armour of the Middle Ages, consisting usually of a canvas base with metal plates

2. archaic a drinking vessel, often of leather

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jack ⁴ British  

/ dʒæk /

noun

1. short for jackfruit

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jack More Idioms  

More idioms and phrases containing jack

• before you can say Jack Robinson

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Etymology

Origin of jack¹

First recorded in 1350–1400; Middle English jakke, Jakke used in addressing any male, especially a social inferior, variant of Jakken, variant of Jankin, equivalent to Jan “John” + -kin diminutive suffix; extended in sense to anything male, and as a designation for a variety of inanimate objects; John, -kin

Origin of jack²

First recorded in 1930–35; shortening of hijack ( def. )

Origin of jack³

First recorded in 1605–15; from Portuguese jaca, from Malayalam cakka

Origin of jack⁴

First recorded in 1325–75; Middle English jakke, from Middle French jaque(s), “short, plain upper garment,” probably after jacques “peasant” ( Jacquerie )

Example Sentences

The losses of the past three years are a side effect of the central bank’s aggressive campaign to jack up interest rates starting in 2022 to combat high inflation.

From The Wall Street Journal • Mar. 25, 2026

Core inflation came in hotter than expected this week, and higher oil prices are almost certainly going to jack up headline numbers.

From Barron's • Mar. 13, 2026

New jack swing made stars of Sweat, Al B. Sure!,

From Los Angeles Times • Feb. 18, 2026

And yet, in a parallel world, it could have been the red, white and blue of the union jack flying in her honour, and not that of the French flag.

From BBC • Feb. 18, 2026

Please know we have asked jack if he felt any undue pressure about any of this, and the answer was a resolute “no.”

From "Wonder" by R. J. Palacio

Related Words

• hoist
• shove