S: (n) catenary (the curve theoretically assumed by a perfectly flexible and inextensible cord of uniform density and cross section hanging freely from two fixed points)
S: (n) Cupid's bow (the double curve of the upper lip when considered to resemble Cupid's bow)
S: (n) scallop, crenation, crenature, crenel, crenelle (one of a series of rounded projections (or the notches between them) formed by curves along an edge (as the edge of a leaf or piece of cloth or the margin of a shell or a shriveled red blood cell observed in a hypertonic solution etc.))
S: (n) spiral (a plane curve traced by a point circling about the center but at increasing distances from the center)
S: (n) helix, spiral (a curve that lies on the surface of a cylinder or cone and cuts the element at a constant angle)
S: (n) perversion (a curve that reverses the direction of something) "the tendrils of the plant exhibited perversion"; "perversion also shows up in kinky telephone cords"