The physical space closely surrounding a person, which can lead to discomfort, anger or anxiety if encroached on.

Alternative form of pre-Hilbert space

(mathematics) An algebraic system used in quantum mechanics to describe quantum states with a variable or unknown number of particles.

(topology) A topological space for which any pair of distinct points are also topologically distinct, i.e., there is an open set which contains one of the points but not the other one.

(topology) An n-dimensional topological space with a distinguished element µ of its nth homology group such that taking the cap product with an element of the kth cohomology group yields an isomorphism to the (n − k)th cohomology group.

(typography) thin space

(in fonts whose digits are of uniform width) A space of non-variable width: ⊣ ⊢ equal to the width of a digit.

(in dated typography) A space of non-variable width: ⊣ ⊢ equal to the width of a period (full stop) or comma, inserted after ⟨“⟩ or ⟨‘⟩ and before ⟨”⟩ or ⟨’⟩ (and sometimes ⟨?⟩ or ⟨!⟩), unless a punctuation mark occurs there. It is Unicode character U+2008. When using X11 input method, the conventional key combination is Compose+Space+Period.

(typography, in fonts whose ideographs are of uniform width) A space of non-variable width: ⊣　⊢ equal to the width of an ideograph, used in Chinese, Japanese, Korean, and other languages that use Siniform ideographs.

plural of space opera