Subspace may refer to:
Mathematics Subspace (mathematics), a particular subset of a parent space A subset of a topological space endowed with the subspace topology Linear subspace, in linear algebra, a subset of a vector space that is closed under addition and scalar multiplication Flat (geometry), a Euclidean subspace Affine subspace, a geometric structure that generalizes the affine properties of a flat Projective subspace, a geometric structure that generalizes a linear subspace of a vector space Multilinear subspace in multilinear algebra, a subset of a tensor space that is closed under addition and scalar multiplication
Science fiction Also known as hyperspace Subspace (Star Trek), a theoretical feature of space-time that facilitates faster-than-light communication and transit
Games SubSpace (video game), a two-dimensional space shooter computer game The Subspace Emissary, the Adventure mode in the video game Super Smash Bros. Brawl
Other uses "Subspace" (song), a 2001 single by Funker Vogt Subspace, in BDSM, a psychological state that can be entered by the submissive participant