jack

noun

ˈjak 

plural jacks

1

a

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

2

a

: 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

5

a

or less commonly Jack chiefly British : man

—usually used as an intensive

… every man jack in the team will want to impress their new manager.

—Malcolm Macdonald

Those two sessions were both open to the public, which meant that any man Jack from the street could have walked in to watch …

—Neil Ashton

b

or Jack : 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 (see royal entry 1 sense 4) mast and spread the royal shrouds (see shroud entry 1 sense 3a)

b

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

7

a

: any of several fishes

especially : any of various carangids (such as a jack crevalle)

b

: a male donkey

c

: jackrabbit

d

: any of several birds (such as a jackdaw)

8

a

: a small usually white target ball used in lawn bowling or bocce

b

: a small national flag flown by a ship

9

slang : money

10

a

: applejack

b

: brandy

11

: jackknife sense 2

12

: monterey jack

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

Synonyms of jack

• cash
• coin
• money
• currency
• bucks
• chips

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

Both have two Thunderbolt 4/USB-C ports on the left and another such port on the right, along with an audio jack. —Michael J. Miller, PC Magazine, 3 June 2026

Microsoft says the Laptop Ultra will include USB-A, USB-C, and HDMI ports, as well as an SD card slot and headphone jack. —Andrew Cunningham, ArsTechnica, 1 June 2026

Haug was a jack of all trades for Smithson Valley as a junior, totaling 2,053 all-purpose yards, including 1,156 receiving yards and 16 total touchdowns. —Steven Johnson june 1, Fort Worth Star-Telegram, 1 June 2026

Components like flashing, pipe jacks, vents and gutters are frequently the first to show signs of trouble, even when the roofing material above them looks intact. —David Nye, The Orlando Sentinel, 27 May 2026

Word History

Etymology

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

First Known Use

1548, in the meaning defined at sense 5a

Phrases Containing jack

• high-low-jack
• jack bean
• jack cheese
• jack crevalle
• jack in
• jack-in-the-box
• jack-in-the-pulpit
• jack into
• jack mackerel
• jack-of-all-trades
• jack-of-all-trades, master of none
• jack off
• jack-o'-lantern
• jack pine
• jack plane
• jack salmon
• jack stand
• jack-tar
• jack-up
• jumping jack
• man jack
• new jack
• new jack swing
• pepper jack
• pepper jack cheese
• screw jack
• union jack
• yellow jack

Rhymes for jack

• ack
• brack
• clack
• crack
• dak
• flack
• flak
• hack
• knack
• lac
• lack
• lak

Kids Definition

jack

1 of 2 noun

ˈjak 

1

a

: man entry 1 sense 1a

b

often capitalized : sailor

2

a

: a device for turning a spit (as in roasting meat)

b

: any of various portable devices for applying pressure or lifting a heavy body (as an automobile or a building) a short distance

3

: any of various animals: as

a

: a male donkey

b

: jackrabbit

4

a

: a small national flag flown by a ship

b

: a small six-pointed metal object used in a game

c

plural : a game played with jacks

5

: a playing card bearing the figure of a soldier or servant

6

slang : money sense 1a

7

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

jack

2 of 2 verb

1

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

2

: increase entry 1 sense 1, raise

jack up prices

jacker noun