A cloister (from Latin claustrum) is a part of cathedral, monastic and abbey architecture. A cloister consists usually of four corridors, with a courtyard or garth in the middle. It is intended to be both covered from the rain, but open to the air. The attachment of a cloister to a Cathedral church usually indicates that it is (or was once) a monastic foundation.
Cloistered (or "Claustral") life is also another name for the life of a monk or nun in the enclosed religious orders; the modern English term enclosure is used in contemporary Catholic church law to mean cloistered, and cloister is sometimes used as a synonym for monastery.
In medieval times, cloisters served the primary function of quiet meditation or study gardens.