What is "exterior angle"

Exterior \Ex*te"ri*or\, a. [L. exterior, compar. of exter or exterus on the outside, outward, foreign, strange, a compar. fr. ex: cf. F. ext['e]rieur. See Ex-, and cf. Extreme, Interior.]

1. External; outward; pertaining to that which is external; -- opposed to interior; as, the exterior part of a sphere.

   Sith nor the exterior nor the inward man Resemble that it was.
   --Shak.

2. External; on the outside; without the limits of; extrinsic; as, an object exterior to a man, opposed to what is within, or in his mind.

   Without exterior help sustained.
   --Milton.

3. Relating to foreign nations; foreign; as, the exterior relations of a state or kingdom.

   Exterior angle (Geom.), the angle included between any side of a triangle or polygon and the prolongation of the adjacent side; also, an angle included between a line crossing two parallel lines and either of the latter on the outside.

   Exterior side (Fort.), the side of the polygon upon which a front of fortification is formed.
   --Wilhelm.

   Note: See Illust. of Ravelin.

n. (context geometry English) An angle formed between one side of a polygon and an extension of an adjacent side.

n. the supplement of an interior angle of a polygon [syn: external angle]