the world > relative properties > number > geometry > surface > [adjective] > relating to plane surfaces > of nature of (4)
Geometry. = plane, adj. 1. Obsolete.
Geometry. Of a surface: perfectly flat or level, without curvature, so that every straight line joining any two points of the surface lies wholly…
Of or relating to straight lines and planes; satisfying the axioms of Euclidean geometry, flat.