exterior angle

noun Geometry.

an angle formed outside parallel lines by a third line that intersects them.
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.

Origin of exterior angle

First recorded in 1885–90
Dictionary.com Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2019

British Dictionary definitions for exterior angle

exterior angle


an angle of a polygon contained between one side extended and the adjacent side
any of the four angles made by a transversal that are outside the region between the two intersected lines
Collins English Dictionary - Complete & Unabridged 2012 Digital Edition © William Collins Sons & Co. Ltd. 1979, 1986 © HarperCollins Publishers 1998, 2000, 2003, 2005, 2006, 2007, 2009, 2012

Science definitions for exterior angle

exterior angle
[ ĭk-stîrē-ər ]

The angle formed between a side of a polygon and an extended adjacent side. Compare interior angle.
The American Heritage® Science Dictionary Copyright © 2011. Published by Houghton Mifflin Harcourt Publishing Company. All rights reserved.