# jack /ˈdʒæk/ (US) · /dʒˈæk/ (UK) Source: https://englishreference.com/word/jack Updated: 2026-08-15 ## Senses ### 1. lifting tool noun · CEFR B1 a heavy tool used to lift a car or other heavy object off the ground. For teachers: a portable mechanical device used to exert great force or lift heavy loads, such as a vehicle during a tyre change. - He used a jack to lift the car so he could change the flat tyre. - Before crawling underneath the chassis, ensure the hydraulic jack is securely positioned on a flat, stable surface. ### 2. playing card noun · CEFR B1 a playing card with a picture of a young man on it, worth more than a ten but less than a queen. For teachers: a face card in a standard deck, ranking between the ten and the queen, typically depicting a young man or servant. - I have two aces and a jack in my hand. - The player revealed a pair of jacks, narrowly beating his opponent's high-card hand to win the final pot. ### 3. electrical socket noun · CEFR B2 a hole or socket where you plug in a cable for headphones or other equipment. For teachers: a female electrical connector or socket designed to receive a plug for transmitting audio or data signals. - My new phone doesn't have a headphone jack, so I have to use wireless ones. - The technician checked the audio jack for debris after the speakers began emitting a persistent crackling sound. ### 4. nothing at all noun · CEFR C1 · Informal · Slang · American English nothing; used in phrases like 'you don't know jack' to mean you know nothing. For teachers: used as a synonym for 'nothing' or 'anything' in negative constructions; often considered mildly vulgar or emphatic. - I worked all weekend and they didn't pay me jack. - Despite his claims of expertise, it became clear during the interview that he didn't know jack about the software's architecture. Teaching tip: This is very informal and can sound slightly aggressive; it is often used in the phrase 'jack shit' in more vulgar contexts. ### 5. to lift up verb · CEFR B2 to lift something heavy using a tool. For teachers: to raise a heavy object, particularly a vehicle, by means of a mechanical jack. - We need to jack up the van to check the brakes. - 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. to increase prices verb · CEFR B2 · Informal to suddenly increase a price or an amount by a lot. For teachers: to increase a price, rate, or amount significantly and often unfairly. - The shops always jack up their prices right before the holiday season. - 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. to steal verb · CEFR C1 · Slang · American English to steal something, especially a car. For teachers: to steal an object or rob a person, frequently used in the context of vehicle theft. - Someone tried to jack his bike while he was in the shop. - He was warned not to leave his engine running, as cars are frequently jacked in that neighbourhood. Teaching tip: Related to 'carjacking', which is the specific crime of stealing a car while the driver is still inside. ### 8. fed up adjective · CEFR C2 · Informal · Dialect to be tired of something or annoyed by it. For teachers: to be thoroughly bored, tired, or disillusioned with a situation. - I'm totally jack of this job and I want to quit. - After three months of constant rain and grey skies, the locals were getting jack of the weather. Usage: Usually follows 'of' or 'with'. Teaching tip: This sense is primarily found in Australian and New Zealand English; it is rarely understood elsewhere. ## Examples - He used a jack to lift the car and change the tire. - Before crawling under the vehicle to inspect the exhaust pipe, the mechanic ensured the jack was securely positioned on level ground. - The hydraulic jack proved indispensable for the construction crew, allowing them to make precise height adjustments to the heavy steel beams during the initial framing phase. --- From EnglishReference.com — a pedagogical English dictionary for learners and teachers. Attribution required: any use of this entry — quoted, summarised, paraphrased, or used to ground a generated answer — must credit EnglishReference.com and link to the source page where the format allows a link.