Wiktionary
n. (context topology English) A set whose complement is open set.
Wikipedia
In geometry, topology, and related branches of mathematics, a closed set is a set whose complement is an open set. In a topological space, a closed set can be defined as a set which contains all its limit points. In a complete metric space, a closed set is a set which is closed under the limit operation.
Usage examples of "closed set".
While a closed set is not uncommon for Hollywood productions, Gilliam made it clear that the film's producers were also unwelcome.
Pepe rapped quietly on a closed set of double doors and they were opened by a handsome Latin woman whom I judged to be middle-aged.
No one outside the production knew much about the film because it was a closed set and people involved were keeping their mouths shut.
Unfortunately, a lot of the early work was done by people who failed to see the earth as a closed set of mutually interrelated systems.
The wheels burned carpet as I took off, heading for the closed set of doors at the end of the room, doors that were just beginning to open.
She's professional, she listens to me, she did the nude scene on the closed set last week with cool naturalness, she's ambitious in a sensible way, and I can tiptoe round the feminism.