imaginary geometry

Etymology
, coined by mathematician, probably influenced by , although his precise reasoning is unknown.

Noun

 * 1)  Absolute geometry, an axiomatised geometry in which the parallel postulate is absent and not replaced by an alternative, and of which Euclidean geometry and some non-Euclidean geometries are subtypes.
 * 2) * 1879, Frederick Pollock, Introduction, Part 1: Biographical, Leslie Stephen, Frederick Pollock (editors),, Lectures and Essays, Volume 1, , page 14,
 * He[Clifford] liked talking about imaginary geometry, as a matter of pure amusement, to anyone interested in it. But at the same time he attached a serious import to it.

Translations

 * Russian: мни́мая геометрия