Other forms: jacks, jacked
A jack is the device that lifts one corner of something far too heavy to lift by hand. You slide it under the car, pump the handle, and the wheel rises clear of the road so you can change it.
As a verb, jack up means lift with a jack — and away from cars it means raise sharply: they jacked up the rent again. A jack is also the playing card between the ten and the queen, and the socket you push a headphone plug into is a jack. In informal American English, jack on its own means nothing at all: he knows jack about engines. A jack of all trades can do a bit of everything and is master of none. The word hides inside plenty of others too: jackpot, jackknife, jackhammer.
1nounjackA device for lifting something heavy a short distance off the ground.
“There is a jack and a spare wheel under the boot floor.”
2verbraiseTo lift something with a jack; also, to raise a price or level sharply.
“They jacked the car up on the verge and had the wheel off in ten minutes.”
3nounplayingThe playing card ranking between the ten and the queen.
“He turned over the jack of spades and took the hand.”
4nounsocketA socket that a plug fits into, especially for audio.
“The old amplifier still has a headphone jack on the front.”
Too few real examples of this word to estimate which sense is commonest.
jack is a lifting device.
Jack is a man's name doing a machine's work. It came through Middle English jakke from Anglo-Norman jacke, and behind that stands Jacques, the French name used for any ordinary peasant. Call every labourer Jack for long enough and the name slides onto the thing that labours for you — the small strong device that lifts what a man cannot.
Middle English
jakke
English, today
jack
Built from
From Middle English jakke. Middle English jakke, from Anglo-Norman jacke, Middle French jaque, jacque, from jacques (“peasant”), from the proper name Jacques. Compare jacquerie.
Etymology from Wiktionary, CC BY-SA