use-icon

HOW TO USE THE DICTIONARY

Learn what the dictionary tells you about words.

Get Started Now!

Some compound words (like bus rapid transit, dog whistle, or identity theft) don’t appear on the drop-down list when you enter them into the search window. If a compound term doesn’t appear in the drop-down list, try entering the term into the search window and then hit the search button (instead of the “enter” key). Alternatively, begin searches for compound terms with a quotation mark.

use-icon

THE USAGE PANEL

The Usage Panel is a group of nearly 200 prominent scholars, creative writers, journalists, diplomats, and others in occupations requiring mastery of language. The Panelists are surveyed annually to gauge the acceptability of particular usages and grammatical constructions.

The Panelists

puzzle-icon

NEED HELP SOLVING A CROSSWORD PUZZLE?

Go to our Crossword Puzzle Solver and type in the letters that you know, and the Solver will produce a list of possible solutions.

open-icon

INTERESTED IN DICTIONARIES?

Check out the Dictionary Society of North America at http://www.dictionarysociety.com

open-icon

AMERICAN HERITAGE DICTIONARY APP

The new American Heritage Dictionary app is now available for iOS and Android.

scroll-icon

INDO-EUROPEAN & SEMITIC ROOTS APPENDICES

Thousands of entries in the dictionary include etymologies that trace their origins back to reconstructed proto-languages. You can obtain more information about these forms in our online appendices:

Indo-European Roots

Semitic Roots

The Indo-European appendix covers nearly half of the Indo-European roots that have left their mark on English words. A more complete treatment of Indo-European roots and the English words derived from them is available in our Dictionary of Indo-European Roots.

open-icon

OPEN DICTIONARY PROJECT

Share your ideas for new words and new meanings of old words!

Start Sharing Now!

100-words-icon

See word lists from the best-selling 100 Words Series!

Find out more!

jack (jăk)
Share:
n.
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, 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.
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. A device used for turning a spit.
8. 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.
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.
14. Applejack.
15. Slang A small or worthless amount: You don't know jack about that.
v. jacked, jack·ing, jacks
v.tr.
1. To hunt or fish for with a jacklight: hunters illegally jacking deer.
2.
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.
4. Slang
a. To steal: Someone jacked my bike.
b. To rob or cheat: The dealer jacked me on the price.
v.intr.
1. To hunt or fish by using a jacklight.
2. To plug into an electronic device by means of a jack.
Phrasal Verbs:
jack around
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.
jack up
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.]

jacker n.
(click for a larger image)
jack
floor jack

The American Heritage® Dictionary of the English Language, Fifth Edition copyright ©2017 by Houghton Mifflin Harcourt Publishing Company. All rights reserved.
 

This website is best viewed in Chrome, Firefox, Microsoft Edge, or Safari. Some characters in pronunciations and etymologies cannot be displayed properly in Internet Explorer.