Definition of cap
1 a
: a head covering especially with a visor and no brim
b
: a distinctive head covering emblematic of a position or office: such as
(1)
: a cardinal's biretta
(2)
: mortarboard
2
: a natural cover or top: such as
a
: an overlying rock layer that is usually hard to penetrate
c
: the top of a bird's head or a patch of distinctively colored feathers in this area
3 a
: something that serves as a cover or protection especially for a tip, knob, or end
- a bottle cap
b
: a fitting for closing the end of a tube
d
: an artificial crown for a tooth
4
: an overlaying or covering structure
5
: a paper or metal container holding an explosive charge (as for a toy pistol)
6
: an upper limit (as on expenditures) : ceiling
- a cap on military spending
7
: the symbol ∩ indicating the intersection of two sets — compare cup 9
8
: a cluster of molecules or chemical groups bound to one end or a region of a cell, virus, or molecule
—
cap in hand
: in a respectful, humble, or sometimes fearful manner
- went cap in hand to the governor to seek more funds for education
