plain/plane

plain (plān)

Adjective

• Free from obstructions; open; clear: in plain view.
• Obvious to the mind; evident: make one's intention plain.
• Not elaborate or complicated; simple: plain food.
• Straightforward; frank or candid: plain talk.
• Not mixed with other substances; pure: plain water.

Noun

• An extensive, level, usually treeless area of land.
• A broad level expanse, as a part of the sea floor or a lunar mare.
• Something free of ornamentation or extraneous matter.

plane (plān)

Noun

• Mathematics. A surface containing all the straight lines that connect any two points on it.
• A flat or level surface.
• A level of development, existence, or achievement: scholarship on a high plane.
• An airplane or hydroplane.
• A supporting surface of an airplane; an airfoil or wing.

Adjective

• Mathematics. Of or being a figure lying in a plane: a plane curve.
• Flat; level.