exterior angle

noun

, Geometry.

1. an angle formed outside parallel lines by a third line that intersects them.
2. an angle formed outside a polygon by one side and an extension of an adjacent side; the supplement of an interior angle of the polygon.

exterior angle

noun

1. an angle of a polygon contained between one side extended and the adjacent side
2. any of the four angles made by a transversal that are outside the region between the two intersected lines

exterior angle

/ ĭk-stîr′ē-ər /

1. The angle formed between a side of a polygon and an extended adjacent side.
2. Compare interior angle

Word History and Origins

Origin of exterior angle¹

First recorded in 1885–90