Involute /(?)/

In·vo·lute

Involute

a.
  1. Rolled inward from the edges; -- said of leaves in vernation, or of the petals of flowers in æstivation. (Bot.)
  2. Turned inward at the margin, as the exterior lip of the Cyprea. (Zool.)

Involute

n.
  1. A curve traced by the end of a string wound upon another curve, or unwound from it; -- called also evolvent. See Evolute. (Geom.)