cap¹ / kap/ • n. 1. a kind of soft, flat hat without a brim, and sometimes having a visor. ∎  a kind of soft, close-fitting head covering worn for a particular purpose or as a mark of a particular profession or status: a bathing cap. ∎  an academic mortarboard: graduates in cap and gown.2. a protective lid or cover for an object such as a bottle or a camera lens. ∎  Dentistry an artificial protective covering for a tooth. ∎  the top of a bird's head when distinctively colored. ∎  the broad upper part of the fruiting body of most mushrooms and toadstools, at the top of a stem.3. an upper limit imposed on spending or other activities: a cap on legal immigration.4. short for percussion cap.• v. (capped, cap·ping) [tr.] 1. put a lid or cover on: he capped his pen. ∎  (often be capped) form a covering layer or top part of: several towers were capped by domes| [as adj. , in comb.] (-capped) snow-capped mountains. ∎  put an artificial protective covering on (a tooth). ∎  provide a fitting climax or conclusion to: he capped a memorable season by becoming champion. ∎  follow or reply to (a story, remark, or joke) by producing a better or more apposite one: they capped each other's stories.2. (often be capped) place a limit or restriction on (prices, expenditure, or other activity).PHRASES: cap (or hat) in hand humbly asking for a favor: we have to go cap in hand begging for funds.set one's cap for (or at) dated (of a woman) try to attract (a particular man) as a suitor.DERIVATIVES: cap·ful / -ˌfoŏl/ n. (pl. -fuls) .cap² / kap/ • n. Finance short for capitalization: mid-cap companies | small-cap stocks.

cap.
1. Abbreviation of capital

2. Capital, cope, cornice, or crowning or terminal feature, fitting closely on any member, or extending beyond it in horizontal dimensions. Cap-moulding is the cornice-like finish of a dado, pedestal, door-lintel, handrail, or other architectural feature.

3. Domical roof on a windmill.

cap cap and bells the insignia of the professional jester.
cap of liberty a conical cap given to Roman slaves on emancipation, often used as a Republican symbol.
cap of maintenance a cap or hat worn as a symbol of dignity, or carried before a monarch on ceremonial occasions.
if the cap fits, wear it used with reference to the assumed suitability of a name or description to a person's behaviour. An earlier related reference in N. Breton's Pasquil's Fools-Cap (1600), makes it clear that the cap was originally a dunce's cap. (Compare if the shoe fits, wear it.) The saying is recorded from the mid 18th century.

cap OE. cæppe — late L. cappa, poss. f. L. caput head; cf. CAPE 1.
Hence as vb. XV.

CAP • abbr. Civil Air Patrol.