Pronunciation: (ik-stēr'ē-ur),[key] —adj. 1. outer; being on the outer side: the exterior surface; exterior decorations. 2. intended or suitable for outdoor use: exterior paint. 3. situated or being outside; pertaining to or connected with what is outside: the exterior territories of a country.
—n. 1. the outer surface or part; outside.
2. outward form or appearance: She has a placid exterior, but inside she is tormented. 3. Math.the collection of points not contained in the closure of a given set.