Yes, plane is a Scrabble word!

Verb

1. Cut or remove with or as if with a plane

2. Travel on the surface of water

3. Make even or smooth, with or as with a carpenter's plane

Adjective

1. Having a surface without slope, tilt in which no part is higher or lower than another

Noun

1. An aircraft that has a fixed wing and is powered by propellers or jets

2. (mathematics) an unbounded two-dimensional shape

3. A level of existence or development

4. A power tool for smoothing or shaping wood

5. A carpenter's hand tool with an adjustable blade for smoothing or shaping wood