Definition of "subspace"

subspace¹

noun
countable and uncountable, plural subspaces
1. (countable, mathematics) A subset of a space which is a space in its own right.
2. (uncountable, science fiction) Any (often unspecified) method of communicating or travelling faster than light speed.
3. (uncountable, science fiction) An alternative dimension or universe, access to or use of which permits faster-than-light travel or communications; hyperspace.

subspace²

noun
uncountable
1. (BDSM) The psychological state of the submissive or "bottom" during sadomasochistic activity.
  Quotations
  My problem, though, is that when he whips me, I resist going into subspace. He has to whip me for fifteen or twenty minutes before I even begin to feel any psychological effects.
  2000, Gloria G Brame, Come hither: a commonsense guide to kinky sex
  When he was far gone into subspace, pain was enough to make him come.
  2003, Chelsea Shepard, Two Moons: Worthy of a Master Book One