Plane

A plane is a flat surface extending in height and width.

A plane is the path of a moving line; it is a line with breadth. A line closes to become a shape, a bounded plane. Shapes are planes with edges.

In vector–based software, every shape consists of line and fill. A plane can be parallel to the picture surface, or it can skew and recede into space.

Ceilings, walls, floors, and windows are physical planes. A plane can be solid or perforated, opaque or transparent, textured or smooth.