What does jack mean?
Jack is a versatile English word whose meaning depends on context. It can name a male donkey, a lifting device, an electrical socket, a playing card, or, in informal use, a man or laborer. As a verb, jack means to lift something with a mechanical device, while the informal phrase “jack up” means to raise a price, cost, or other amount. The word is especially useful because it connects a literal idea of lifting or plugging in with figurative ideas of increasing, enlarging, or intensifying something. Its electrical and mechanical senses remain common in practical instructions, whereas the laborer sense is often dated or mildly insulting. In cards, a jack ranks below a queen and above a ten.
A male donkey; also a device for lifting or supporting a load, an electrical socket, a playing card ranking below a queen, or an informal term for a man or laborer.
"The farm had one jack and several mares."
The sense meaning an informal male worker is often derogatory and now sounds dated in most contexts.
To lift or support something using a jack; informally, to raise or increase something such as a price.
"They jacked up the price of the subscription without notice."
The informal sense of increasing a price or cost is common in everyday speech.
The plural is regular and is used for multiple devices, cards, male donkeys, or informal references to men.
"The workshop contains several hydraulic jacks."
One word can mean a donkey, a lifting tool, an electrical socket, a playing card, and a sudden increase—making jack one of English's most versatile everyday words.
Reviewed by Deb Chak, Editor. AI-assisted content curated by RJS Tech Solutions LLP.
Where does jack come from?
The word comes through the name Jack, a traditional diminutive of John, and the sense “male donkey” developed in the Middle English period. The name was also applied to various mechanical devices, including devices for lifting and devices for drawing water. The electrical sense developed later by analogy with a male plug, while the verb meanings “lift” and “raise” grew from the mechanical senses.
Related word forms
How jack is actually used
The word is highly informal and sometimes disparaging when used for a man or worker, as in phrases such as “every man jack,” although that expression is now old-fashioned. “Jack up” is especially common in British and American informal English. In electrical contexts, “jack” is a socket, while “plug” is the connector that enters it.
Easily confused with jack
A jack is a male donkey, whereas a jenny is a female donkey.
A jack is the socket into which a plug is inserted; it is the plug that fits into the jack.