Dictionary.com
definitions

jack

1
[jak]
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. (initial capital letter) Informal. 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. jacks,(used with a singular verb)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. (initial capital letter) a sailor.
  11. a lumberjack.
  12. applejack.
  13. jack rabbit.
  14. a 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.
verb (used with object)
  1. to lift or move (something) with or as if with a jack (usually followed by up): to jack a car up to change a flat tire.
  2. Informal. to increase, raise, or accelerate (prices, wages, speed, etc.) (usually followed by up).
  3. Informal. to boost the morale of; encourage (usually followed by up).
  4. Slang. to mess up, ruin, or injure (usually followed by up): 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 Phrases
  1. jack off, Slang: Vulgar. to masturbate.
Idioms
  1. every man jack, everyone without exception: They presented a formidable opposition, every man jack of them.

Origin of jack

1
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 -kin; extended in sense to anything male, and as a designation for a variety of inanimate objects
Dictionary.com Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2018
British Dictionary definitions for jack off

Jack

noun
  1. I'm all right, Jack British informal
    1. a remark indicating smug and complacent selfishness
    2. (as modifier)an ``I'm all right, Jack'' attitude

jack

1
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 nationalityCompare 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. US a slang word for money
  16. every man jack everyone without exception
  17. the jack Australian slang venereal disease
adjective
  1. jack of Australian slang tired or fed up with (something)
verb (tr)
  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 US and Canadian to hunt (fish or game) by seeking them out or dazzling them with a flashlight
See also jack in, jacks, jack up

Word Origin for jack

C16 jakke, variant of Jankin, diminutive of John

jack

2

jak

noun
  1. short for jackfruit

Word Origin for jack

C17: from Portuguese jaca; see jackfruit

jack

3
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

Word Origin for jack

C14: from Old French jaque, of uncertain origin
Collins English Dictionary - Complete & Unabridged 2012 Digital Edition © William Collins Sons & Co. Ltd. 1979, 1986 © HarperCollins Publishers 1998, 2000, 2003, 2005, 2006, 2007, 2009, 2012
Word Origin and History for jack off

Jack

masc. proper name, 1218, probably an anglicization of Old French Jacques (which was a diminutive of Latin Jacobus; see Jacob), but in English the name always has been associated with Johan, Jan "John," and some have argued that it is a native formation.

Alliterative coupling of Jack and Jill is from 15c. (Ienken and Iulyan). In England, applied familiarly or contemptuously to anybody (especially one of the lower classes) from late 14c. Later used especially of sailors (1650s; Jack-tar is from 1781). In U.S., as a generic name addressed to an unknown stranger, attested from 1889.

jack

n.

late 14c., jakke "a mechanical device," from the masc. name Jack. The proper name was used in Middle English for "any common fellow" (mid-14c.), and thereafter extended to various appliances replacing servants (1570s). Used generically of men (jack-of-all-trades, 1610s), male animals (1620s, see jackass, jackdaw, etc.), and male personifications (1520s, e.g. Jack Frost, 1826).

As the name of a device for pulling off boots, from 1670s. The jack in a pack of playing cards (1670s) is in German Bauer "peasant." Jack shit "nothing at all" is attested by 1968, U.S. slang. The plant jack-in-the-pulpit is attested by 1837. Jack the Ripper was active in London 1888. The jack of Union Jack is a nautical term for "small flag at the bow of a ship" (1630s).

jack

v.

1860, jack up "hoist, raise," American English, from the noun (see jack (n.)). Figurative sense "increase (prices, etc.)" is 1904, American English. Related: Jacked; jacking. Jack off (v.) "to masturbate" is attested from 1916, probably from jack (n.) in the sense of "penis."

Online Etymology Dictionary, © 2010 Douglas Harper
Idioms and Phrases with jack off

jack off

see jerk off.

jack

In addition to the idioms beginning with jack

  • jack off
  • jack up

also see:

  • before you can say Jack Robinson
The American Heritage® Idioms Dictionary Copyright © 2002, 2001, 1995 by Houghton Mifflin Harcourt Publishing Company. Published by Houghton Mifflin Harcourt Publishing Company.