WordNet sense 1 (the boundary line or the area immediately inside the boundary):

margin, perimeter, margin

WordNet sense 2 (the boundary of a surface):

edge

WordNet sense 3 (a line that indicates a boundary):

borderline, delimitation, mete, boundary line

WordNet sense 4 (a decorative recessed or relieved surface on an edge):

molding, moulding

WordNet sense 5 (form the boundary of; be contiguous to):

bound

WordNet sense 6 (enclose in or as if in a frame):

frame, frame in

WordNet sense 7 (extend on all sides of simultaneously; encircle):

skirt, surround

WordNet sense 8 (lie adjacent to another or share a boundary):

abut, adjoin, march, butt against