(linear algebra, mathematical analysis) A vector space over the field of real numbers.

(chemistry) A type of three-dimensional molecular model, where the atoms are represented by spheres whose radii are proportional to the radii of the atoms, and whose center-to-center distances are proportional to the distances between the atomic nuclei, all in the same scale.

(physics) The Newtonian concept of an unchanging and unchangeable reference system of time and spatial coordinates that is the same for all observers

(mathematics) An incomplete metric space with an inner product.

(mathematical analysis) a curve whose range contains the entire 2-dimensional unit square (or the 3-dimensional unit cube)

An artificial satellite in low-earth orbit operating by a number of cooperating space programmes.

(fandom slang) An implausible point of divergence from reality, used as a plot device in alternate history.

(of text) Formatted so that there is one half of a blank line between each line of text

Synonym of Calabi-Yau manifold

(physics) Synonym of time crystal