CAP.

cap [countable]

1

hat

a) a type of flat hat that has a curved part sticking out at the front, and is often worn as part of a uniform:

a baseball cap

old men in flat caps

a chauffeur's peaked cap

b) a covering that fits very closely to your head:

a swimming cap

a shower cap

c) a type of simple hat that fits very closely to your head, worn especially by women in the past:

a white lace cap

2

covering

a protective covering that you put on the end or top of an object [= top]:

Make sure you put the cap back on the pen.

a bottle cap

3

limit

an upper limit that is put on the amount of money that someone can earn, spend, or borrow:

a cap on local council spending

4

sport

British English

a) if a sports person wins a cap or is given a cap, he or she is chosen to play for their country:

He won his first England cap against Wales in 1994.

b) a sports person who has played for his or her country:

Mason is one of two new caps in the team.

5

small explosive

a small paper container with explosive inside it, used especially in toy guns

6

sex

a contraceptive made of a round piece of rubber that a woman puts inside her vagina [= diaphragm]

7

 go cap in hand (to somebody)

British English go hat in handAmerican English to ask for money or help in a very respectful way, from someone who has a lot more power than you:

Elderly people should receive a heating allowance every winter, instead of having to go cap in hand to the government.

➔ flat cap, ice cap, kneecap, mob cap, skull cap, toecap

 ; ➔ a feather in your cap

 at feather1 (2)

 ; ➔ if the cap fits (, wear it)

 at fit1 (8)

 ; ➔ put your thinking cap on

 at thinking1 (3)

Definition from the Longman Dictionary of Contemporary English
Advanced Learner's Dictionary