\ˈjak \
plural jacks

Definition of jack 

(Entry 1 of 2)

1a jacks plural in form but singular in construction : a game played with a set of small objects that are tossed, caught, and moved in various figures

b : a small 6-pointed metal object used in the game of jacks

2a : a playing card carrying the figure of a soldier or servant and ranking usually below the queen

b : jackpot sense 1b(2)

3 : any of various usually mechanical devices: such as

a : a usually portable mechanism or device for exerting pressure or lifting a heavy body a short distance

b : a device for turning a spit

4 : a female fitting in an electric circuit used with a plug to make a connection with another circuit

5a : man usually used as an intensive in such phrases as every man jack

b often capitalized : sailor

c(1) : servant, laborer

(2) : lumberjack

6 : something that supports or holds in position: such as

a : an iron bar at a topgallant masthead to support a royal mast and spread the royal shrouds

b : a wooden brace fastened behind a scenic unit in a stage set to prop it up

7a : any of several fishes especially : any of various carangids

b : a male donkey

c : jackrabbit

d : any of several birds (such as a jackdaw)

8a : a small white target ball in lawn bowling

b : a small national flag flown by a ship

9 slang : money

10a : applejack

b : brandy

13 US slang : anything at all used in negative constructions In short, Dinger or Homer or whoever it was who wrote the Odyssey didn't know jack about travel.— Steve Rushin


jacked; jacking; jacks

Definition of jack (Entry 2 of 2)

transitive verb

1a : to move or lift by or as if by a jack

b : to raise the level of usually used with up jack up the price

c : to take to task

2 : to hunt or fish for at night with a jacklight

intransitive verb

: to hunt or fish at night with a jacklight

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Other Words from jack


jacker noun

Examples of jack in a Sentence


I'd buy that watch, but I don't have the jack right now. a Portuguese ship flying the national jack

Recent Examples on the Web: Noun

The laundry room and five of the home's six bedrooms are on the second floor, including the master suite and two children's rooms connected by a jack-and-jill bathroom. Emma Kate Fittes, Indianapolis Star, "Hot Property: This six-bedroom home in Carmel's West Clay could be yours for $950,000," 6 July 2018 Then add crisscross pieces of applewood smoked bacon, melted pepper jack and a fried egg. Anna Caplan, star-telegram, "Fries? Check. Wonderfully messy sandwiches? Check. Roll of paper towels? Absolutely," 6 June 2018 Lower knee and then jump legs out and in again, performing another jack and then lift right knee up. Health.com, "This Super-Fun, Strength-Based Cardio Dance Workout Will Make You Forget You Are Exercising," 8 Mar. 2018 Rosario, meanwhile, is slashing .301/.342/.536 with 18 jacks and 53 RBI. Michael Beller, SI.com, "A Look at The Fantasy All-Stars Who Should Find Themselves in D.C.," 9 July 2018 In the early days of telephones, human switchboard operators connected calls manually by plugging a cord into two numbered jacks on a large switchboard. sandiegouniontribune.com, "June 18, 1919: Telephone operators strike," 18 June 2018 Doyel: Why taking a risk on Tyreke Evans is worth it More: What Pacers fans need to know about Tyreke Evans Evans was NBA Rookie of the Year in 2010 with the Sacramento Kings but has fallen into a jack-of-all trades supporting role since then. J. Michael, Indianapolis Star, "Pacers continue push for more offense, bring aboard another scorer in Tyreke Evans," 3 July 2018 Matt Colby/Now News Group 20 Friday Halloween haunts: Enjoy hundreds of exquisite jack-o-lanterns, learn from friendly characters in the enchanted forest and enjoy a magic show and carnival games. Amy Schwabe, Milwaukee Journal Sentinel, "Weekend guide: Farm & Fleet Toyland celebration, Halloween haunts, a haunted ship and more," 18 Oct. 2017 When the stop was finished, Appleby lowered the jack, both dropping the car to the ground and slamming his finger. Fletcher Page, The Courier-Journal, "Former U of L punter Josh Appleby now holds vital role for NASCAR team," 13 July 2018

Recent Examples on the Web: Verb

Instead, the team was careless with the ball and had too many possessions end with one or fewer passes before a contested shot was jacked up. William Guillory, NOLA.com, "'Inexcusable' 2nd quarter dooms Pelicans in Game 1 loss to Warriors," 29 Apr. 2018 Meanwhile, the phenomenon of crypto-jacking—in which hackers hijack your computer to mine digital currency—has quickly morphed from a novelty to a big league threat. Robert Hackett, Fortune, "Can Machines Save Us From the the Machines?," 17 Feb. 2018 Democrats, by contrast, insisted that the tax cuts would do little beyond enabling corporations to artificially jack up their share prices by plowing ungodly sums of money into stock buybacks. Eric Levitz, Daily Intelligencer, "Corporations Invested Their Tax Cuts Into Stock Buybacks That Didn’t Even Work," 9 July 2018 The lawsuit was dropped a few months later — but his rent was jacked up from $2,400 to $4,000 a month. Trisha Thadani, SFChronicle.com, "Supervisor moves to strengthen renter protections in San Francisco," 10 July 2018 First, crypto-jacking scripts require little skill to implement. Robert Stevens, chicagotribune.com, "How your smart fridge and TV might be mining bitcoin for criminals," 4 July 2018 Kooky 18th-century protectionism will jack up prices on American families — and will prompt retaliation from other countries. David Jackson, USA TODAY, "Trump claims 'trade wars' are 'easy to win' day after tariff talk roils stock market," 2 Mar. 2018 Leon rejected the government's argument that the phone and pay-TV giant's $81 billion takeover of the entertainment conglomerate would hurt competition, limit choices and jack up prices for consumers to stream TV and movies. Marcy Gordon, chicagotribune.com, "Justice Department appealing judge's OK of AT&T-Time Warner merger," 12 July 2018 There are newspaper journalists who seem far more interested in getting on TV, and jacking up their Twitter numbers, than being fair or accurate. Dave Barry, miamiherald, "Dave Barry: Sorry, I'm not feeling funny today — my heart aches for slain journalists," 29 June 2018

These example sentences are selected automatically from various online news sources to reflect current usage of the word 'jack.' Views expressed in the examples do not represent the opinion of Merriam-Webster or its editors. Send us feedback.

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First Known Use of jack


1548, in the meaning defined at sense 5a


circa 1833, in the meaning defined at intransitive sense

History and Etymology for jack


Middle English Jacke, familiar term of address to a social inferior, nickname for Johan John

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Phrases Related to jack

jack in

the Union Jack

Statistics for jack

Last Updated

19 Oct 2018

Look-up Popularity

Time Traveler for jack

The first known use of jack was in 1548

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More Definitions for jack



English Language Learners Definition of jack

: a device used for lifting something heavy (such as a car)

: a playing card that has a picture of a soldier or servant and that is worth more than a ten and less than a queen

: a small opening where something connects with a wire to something else


\ˈjak \

Kids Definition of jack

 (Entry 1 of 2)

1 : a device for lifting something heavy a short distance

2 : a playing card with the picture of a young man

3 : a small six-pointed usually metal object used in a children's game ( jacks )

4 : a socket used with a plug to connect one electric circuit with another


jacked; jacking

Kids Definition of jack (Entry 2 of 2)

: to move or lift with a special device We need to jack up the car.

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Comments on jack

What made you want to look up jack? Please tell us where you read or heard it (including the quote, if possible).


exaggeratedly or childishly emotional

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