Car‐te″sian (?), a. [From Renatus Cartesius, Latinized from of René Descartes: cf. F. cartésien.] Of or pertaining to the French philosopher René Descartes, or his philosophy.
The Cartesion argument for reality of matter.
Sir W. Hamilton.
Cartesian coördinates(Geom), distance of a point from lines or planes; — used in a system of representing geometric quantities, invented by Descartes. — Cartesian devil, a small hollow glass figure, used in connection with a jar of water having an elastic top, to illustrate the effect of the compression or expansion of air in changing the specific gravity of bodies. — Cartesion oval(Geom.), a curve such that, for any point of the curve mr + m′r′ = c, where r and r′ are the distances of the point from the two foci and m, m′ and c are constant; — used by Descartes.