plane
adjective/pleɪn/
/pleɪn/
[only before noun] (specialist)- completely flat; level
- a plane surface
Word Originadjective early 17th cent.: from Latin planum ‘flat surface’, neuter of the adjective planus ‘plain’. The adjective was suggested by French plan(e) ‘flat’. The word was introduced to differentiate the geometrical senses, previously expressed by plain, from its other meanings.
Check pronunciation:
plane