noun / adjective
plane
A completely flat surface.
Two intersecting planes meet along a straight line.
Etymology
The Latin adjective means flat or level. Geometry makes the idea exact by defining an ideal surface without curvature.
More examples
- The tops of both tables lie in the same plane.
- A plane mirror has a flat reflecting surface.
- The discussion moves to a more abstract plane.
Forms
plane · planes
planar adjective — Relating to or lying in a plane.