Noun

• S: (n) periphery, fringe, outer boundary (the outside boundary or surface of something)
• direct hypernym / inherited hypernym / sister term
• S: (n) boundary, edge, bound (a line determining the limits of an area)
• S: (n) rim (the shape of a raised edge of a more or less circular object)
• S: (n) margin, border, perimeter (the boundary line or the area immediately inside the boundary)
• S: (n) periphery, fringe, outer boundary (the outside boundary or surface of something)
• S: (n) brink, threshold, verge (a region marking a boundary)
• S: (n) upper bound ((mathematics) a number equal to or greater than any other number in a given set)
• S: (n) lower bound ((mathematics) a number equal to or less than any other number in a given set)
• S: (n) thalweg (the middle of the chief navigable channel of a waterway that forms the boundary line between states)
• derivationally related form
• W: (adj) peripheral [Related to: periphery] (on or near an edge or constituting an outer boundary; the outer area) "Russia's peripheral provinces"; "peripheral suburbs"
• W: (adj) fringy [Related to: fringe] (at or constituting a border or edge) "the marginal strip of beach"