What does cap mean?
A cap is, most familiarly, a soft head covering that fits closely to the skull and typically features a projecting peak or visor at the front — think of the classic baseball cap or a woolen flat cap. The word extends naturally to any lid or cover that sits atop something else, from bottle caps to lens caps, and by metaphorical extension it denotes an upper limit, as in a salary cap or a cap on spending. As a verb, 'to cap' means to fit a cover onto something, to impose such a limit, or, figuratively, to bring a sequence of events to a fitting climax, as in 'to cap it all'. Derived ultimately from the Latin 'cappa', meaning a hooded cloak, the word has proven remarkably productive in English, appearing in idioms such as 'cap in hand' and lending its name to the graduation cap worn at ceremonies. It is a short, sturdy word whose meanings all share a common idea: something placed on top.
A soft head covering without a brim, typically having a peak or visor; also, a lid or cover fitted over the top of an object.
"He doffed his cap politely as the lady walked past."
To place a cover on top of something; to set an upper limit on an amount or price; or to follow something with an even better or more striking conclusion.
"The team capped a perfect season with a championship win."
Standard regular plural; used for both head coverings and lids/covers.
"The lost-and-found box was full of caps left behind at the stadium."
The word 'cap' traces back to the Latin word for 'head' — so every time you put one on, you are literally capping your caput.
Reviewed by Deb Chak, Editor. AI-assisted content curated by RJS Tech Solutions LLP.
Etymology of cap
The word 'cap' entered English before the twelfth century as Old English 'cæppe', borrowed from Late Latin 'cappa', which meant a hooded cloak or head covering. From the same Latin root come 'cape', 'chapel' — originally the shrine housing St. Martin's cappa or cloak — and 'chaperon', which once referred to a protective hood. The sense of an upper limit or ceiling developed later, extending the image of something placed on top of something else.
Related word forms
How cap is actually used
Highly versatile across registers: entirely neutral in everyday use, common in figurative expressions like 'cap in hand' (humbly requesting a favor) and 'to cap it all' (as a final, often ironic touch). In informal slang, especially in recent American usage, 'no cap' means 'no lie'. The verb sense 'to cap' can mean either literally covering something or figuratively topping a previous achievement.
Easily confused with cap
A cape is a sleeveless cloak or garment, or a headland of land jutting into water, whereas a cap is a close-fitting head covering with no brim.