- A double curve - An S bend - An S-shaped curve - Double curve - S-shaped curve - A molding, the section of which is the form of the letter S,
with the convex part above; cyma reversa. See Illust. under Cyma. - Hence, any similar figure used for any purpose.
- A leaf, esp. a thin leaf or plate. - A curve of the third order, consisting of two infinite
branches, which have a common asymptote. The curve has a double point,
and a leaf-shaped loop; whence the name. Its equation is x3 + y3 = axy.