planar

adj

Etymology: From Late Latin plānārius (“relating to a plane”), derived from Latin plānus (“flat”, “level”), equivalent to plane + -ar, ultimately from Proto-Indo-European *pleh₂- (“flat”).

1. Of or pertaining to a plane.

   “A planar projection of a three-dimensional object is its projection onto a plane.”

2. Flat, two-dimensional.
3. Able to be embedded in the plane with no edges intersecting.

   “A complete graph with more than four nodes is never planar.”

4. Having a flat profile, not etched into a mesa.