- In mathematics, if a set with certain properties is called a
*space*, then a subset of which with same properties is usually called a**subspace**. Those with entries in Wikipedia are:- Linear subspaces (also called
*vector subspaces*) in linear algebra; - Topological subspaces in topology.

- Linear subspaces (also called
- There is a fictional notion of subspace used in science fiction; see Hyperspace.
- The psychological state of the submissive partner in a BDSM scene is sometimes described as "subspace" or "sub space": see subspace (BDSM)