Adjective

(-)

Sealed, made inaccessible or impassable; not open

(of a store or business) Not operating or conducting trade

Not public.

closed source

a closed committee

(topology, of a set) Having an open complement.

(mathematics, of a set) Such that its image under the specified operation is contained in it.

The set of integers is closed under addition: $\backslash forall\; x,y\backslash in\backslash mathbb\{Z\}\backslash ,x+y\backslash in\backslash mathbb\{Z\}$.

(mathematics, logic, of a formula) Lacking a free variable.

Adjective

(en adjective)

Belonging to, concerning, or accessible only to an individual person or a specific group.

* {{quote-magazine, date=2013-06-14, author=(Jonathan Freedland)

, volume=189, issue=1, page=18, magazine=(The Guardian Weekly) , title= Obama's once hip brand is now tainted , passage=Now we are liberal with our innermost secrets, spraying them into the public ether with a generosity our forebears could not have imagined. Where we once sent love letters in a sealed envelope, or stuck photographs of our children in a family album, now such private material is despatched to servers and clouds operated by people we don't know and will never meet.}}

Not in governmental office or employment.

* {{quote-magazine, date=2013-07-19, author=(Peter Wilby)

, volume=189, issue=6, page=30, magazine=(The Guardian Weekly) , title= Finland spreads word on schools , passage=Imagine a country where children do nothing but play until they start compulsory schooling at age seven. Then, without exception, they attend comprehensives until the age of 16.

Not publicly known; not open; secret.

* {{quote-book, year=1963, author=(Margery Allingham), title=(The China Governess)

, chapter=20 citation , passage=The story struck the depressingly familiar note with which true stories ring in the tried ears of experienced policemen.

Protected from view or disturbance by others; secluded.

Intended only for the use of an individual, group, or organization.

Not accessible by the public.

Not traded by the public.

* {{quote-magazine, date=2013-06-22, volume=407, issue=8841, page=70, magazine=(The Economist)

, title= Engineers of a different kind , passage=Private -equity nabobs bristle at being dubbed mere financiers. Piling debt onto companies’ balance-sheets is only a small part of what leveraged buy-outs are about, they insist. Improving the workings of the businesses they take over is just as core to their calling, if not more so. Much of their pleading is public-relations bluster.}}

Secretive; reserved.

(US, of a room in a medical facility) Not shared with another patient.