border

a line that indicates a boundary

the boundary line or the area immediately inside the boundary

the boundary of a surface

a decorative recessed or relieved surface on an edge

a strip forming the outer edge of something; "the rug had a wide blue border"

extend on all sides of simultaneously; encircle; "The forest surrounds my property"

form the boundary of; be contiguous to

enclose in or as if in a frame; "frame a picture"

provide with a border or edge; "edge the tablecloth with embroidery"

lie adjacent to another or share a boundary; "Canada adjoins the U.S."; "England marches with Scotland"