Perimeter
WordNet
noun
(1) The size of something as given by the distance around it
(2) A line enclosing a plane areas
(3) The boundary line or the area immediately inside the boundary
WiktionaryText
Noun
- The sum of the distance of all the lengths of the sides of an object.
- The outer limits of an area. See Synonyms at circumference.
- The length of such a boundary.
- A fortified strip or boundary usually protecting a military position.