Closed

Closed may refer to:

Mathematics

 * Closure (mathematics), a set, along with operations, for which applying those operations on members always results in a member of the set
 * Closed set, a set which contains all its limit points
 * Closed interval, an interval which includes its endpoints
 * Closed line segment, a line segment which includes its endpoints
 * Closed manifold, a compact manifold which has no boundary
 * Closed differential form, a differential form whose exterior derivative is 0

Other uses

 * Closed (poker), a betting round where no player will have the right to raise
 * Closed (album), a 2010 album by Bomb Factory
 * Closed GmbH, a German fashion brand
 * Closed class, in linguistics, a class of words or other entities which rarely changes