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plane¹

(plān)

1. Mathematics A surface containing all the straight lines that connect any two points on it.

2. A flat or level surface.

3. A level of development, existence, or achievement: scholarship on a high plane.

4. An airplane or hydroplane.

5. A supporting surface of an airplane; an airfoil or wing.

adj.

1. Mathematics Of or being a figure lying in a plane: a plane curve.

2. Flat; level. See Synonyms at level.

[Latin plānum, flat surface, from neuter of plānus, flat; see pelə-² in the Appendix of Indo-European roots. N., sense 4, short for AEROPLANE.]

planeness n.

Indo-European & Semitic Roots Appendices

Thousands of entries in the dictionary include etymologies that trace their origins back to reconstructed proto-languages. You can obtain more information about these forms in our online appendices:

Indo-European Roots

Semitic Roots

The Indo-European appendix covers nearly half of the Indo-European roots that have left their mark on English words. A more complete treatment of Indo-European roots and the English words derived from them is available in our Dictionary of Indo-European Roots.

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