closed circuit noun

1. An electrical circuit in which current flows when voltage is applied
2. A television system in which the transmission is restricted to a limited number of screens connected to the television camera by cables, etc (also closed-circuit television)

closed community noun (ecology)

A plant community that is so dense that no new species can colonize

closed couplet noun (prosody)

Two metrical lines whose grammatical structure and sense concludes at the end of the second line

closed-doorˈ see behind closed doors below.

closed-endˈ adjective

1. Having fixed limits
2. (of an investment trust) offering shares up to a limited number

closed-inˈ adjective

Claustrophobically enclosed

closed-loopˈ adjective

Denoting a computer system in which performance is controlled by comparing output with an expected standard

closedown see close down below.

closed population noun (biology)

A population in which there is no new gene input from outside and in which mutation is the only source of genetic variation

closed scholarship noun

A scholarship open only to those candidates able to fulfil certain criteria, such as attendance at a particular school, etc

closed set noun (mathematics)

A set in which the result of combining any two members of the set using a given operation always results in a member of the original set

closed shop noun

1. An establishment in which only members of a trade union, or of a particular trade union, will be employed
2. The principle or policy implied in such a regulation

closed syllable noun (phonetics)

One ending in a consonant

closing date noun

The date by which something must be submitted, completed, etc

closing price noun

The value of shares on the stockmarket when business stops for the day

closing time noun

The time at which business stops, esp in public houses

behind closed doors

In private, the public being excluded, as in court cases, committee meetings, etc (closed-doorˈ adjective)

close a bargain

To come to an agreement

close down

1. To come to a standstill or stoppage of work
2. (esp in team games, eg football) to slow the pace of a game and prevent the opposition from making any attacking manoeuvres
3. (of a television or radio station) to end a period of broadcasting
4. (of a business) to cease trading (closeˈdown noun)

close in

(of days) to contain a progressively shorter period of daylight, as between the autumnal equinox and the winter solstice

close in upon

To surround and draw near to

close on

To catch up with

close one's eyes (euphemistic)

To die

close one's eyes to

To ignore or disregard purposely

close ranks

1. (of soldiers drawn up in line) to stand closer together in order to present a more solid front to the enemy
2. To unite, make a show of solidarity in order to protect a member or all the members of a group from attack

close up

1. To cease operating
2. To draw together

close with

1. To accede to
2. To grapple or engage in combat with

with closed doors same as behind closed doors (see above).