English Reference
noun · verb · adjective

jack

n. · v. · adj.
US /ˈdʒæk/ UK /dʒˈæk/ jack UK spelling jacking

  1. 01 B1 Intermediate

    n.a heavy tool used to lift a car or other heavy object off the ground.

    n.a portable mechanical device used to exert great force or lift heavy loads, such as a vehicle during a tyre change.

    Simple

    He used a jack to lift the car so he could change the flat tyre.

    In context

    Before crawling underneath the chassis, ensure the hydraulic jack is securely positioned on a flat, stable surface.

  2. 02 B1 Intermediate

    n.a playing card with a picture of a young man on it, worth more than a ten but less than a queen.

    n.a face card in a standard deck, ranking between the ten and the queen, typically depicting a young man or servant.

    Simple

    I have two aces and a jack in my hand.

    In context

    The player revealed a pair of jacks, narrowly beating his opponent's high-card hand to win the final pot.

    knave
  3. 03 B2 Upper Intermediate Electronics

    n.a hole or socket where you plug in a cable for headphones or other equipment.

    n.a female electrical connector or socket designed to receive a plug for transmitting audio or data signals.

    Simple

    My new phone doesn't have a headphone jack, so I have to use wireless ones.

    In context

    The technician checked the audio jack for debris after the speakers began emitting a persistent crackling sound.

  4. 04 C1 Advanced InformalSlangAmerican English

    n.nothing; used in phrases like 'you don't know jack' to mean you know nothing.

    n.used as a synonym for 'nothing' or 'anything' in negative constructions; often considered mildly vulgar or emphatic.

    Simple

    I worked all weekend and they didn't pay me jack.

    In context

    Despite his claims of expertise, it became clear during the interview that he didn't know jack about the software's architecture.

    Teacher's tip

    This is very informal and can sound slightly aggressive; it is often used in the phrase 'jack shit' in more vulgar contexts.

  5. 05 B2 Upper Intermediate

    v.to lift something heavy using a tool.

    v.to raise a heavy object, particularly a vehicle, by means of a mechanical jack.

    Simple

    We need to jack up the van to check the brakes.

    In context

    The mechanic jacked up the front end of the car to inspect the suspension for signs of wear.

    Usage

    Often used with the particle 'up'.

  6. 06 B2 Upper Intermediate Informal

    v.to suddenly increase a price or an amount by a lot.

    v.to increase a price, rate, or amount significantly and often unfairly.

    Simple

    The shops always jack up their prices right before the holiday season.

    In context

    Landlords in the city centre have been jacking up rents so high that local businesses are being forced to close.

    Usage

    Usually used with the particle 'up'.

  7. 07 C1 Advanced SlangAmerican English

    v.to steal something, especially a car.

    v.to steal an object or rob a person, frequently used in the context of vehicle theft.

    Simple

    Someone tried to jack his bike while he was in the shop.

    In context

    He was warned not to leave his engine running, as cars are frequently jacked in that neighbourhood.

    Teacher's tip

    Related to 'carjacking', which is the specific crime of stealing a car while the driver is still inside.

  8. 08 C2 Proficiency InformalDialect

    adj.to be tired of something or annoyed by it.

    adj.to be thoroughly bored, tired, or disillusioned with a situation.

    Simple

    I'm totally jack of this job and I want to quit.

    In context

    After three months of constant rain and grey skies, the locals were getting jack of the weather.

    Usage

    Usually follows 'of' or 'with'.

    Teacher's tip

    This sense is primarily found in Australian and New Zealand English; it is rarely understood elsewhere.


From Middle English Jackin, Jankyn, a popular pet form of John; rarely also an anglicized form of French Jacques (equivalent of Jacob and James). It can be also used as nickname for Jacob. Though the name was originally a pet form, it has become more of an independent name. Equivalent to John + -kin, Jake or Jacques. See also Middle French Hennequin, Jannequin and Middle Dutch Janneken.

Etymology adapted from Wiktionary, available under CC BY-SA 4.0.

This entry
Origin French Jacques
Level B1 · Intermediate
Frequency Very common
Updated