Perimeter

n.	1.	(Geom.) The outer boundary of a body or figure, or the sum of all the sides.
	2.	An instrument for determining the extent and shape of the field of vision.

Noun	1.	perimeter - the boundary line or the area immediately inside the boundary Synonyms: margin, border
	2.	perimeter - a line enclosing a plane areas
	3.	perimeter - the size of something as given by the distance around it Synonyms: circumference

alentours, ambience, ambit, border, borderlands, borderline, boundaries, boundary, bounds, bourn, bourns, brim, brink, circle, circuit, circumambiencies, circumference, circumjacencies, circumscription, circumstances, compass, confines, context, coordinates, edge, edges, entourage, environing circumstances, environment, environs, fringe, fringes, gestalt, habitat, hem, limitations, limits, marches, margin, metes, metes and bounds, milieu, neighborhood, outlines, outposts, outskirts, pale, parameters, periphery, precincts, purlieus, situation, skirt, skirts, suburbs, surroundings, total environment, verge, verges, vicinage, vicinity