Source : Webster's Revised Unabridged Dictionary (1913)

Involute \In"vo*lute\, Involuted \In"vo*lu`ted\, a. [L.
   involutus, p. p. of involvere. See {Involve}.]
   1. (Bot.) Rolled inward from the edges; -- said of leaves in
      vernation, or of the petals of flowers in [ae]stivation.
      --Gray.

   2. (Zo["o]l.)
      (a) Turned inward at the margin, as the exterior lip of
          the Cyprea.
      (b) Rolled inward spirally.

Involute \In"vo*lute\, n. (Geom.)
   A curve traced by the end of a string wound upon another
   curve, or unwound from it; -- called also {evolvent}. See
   {Evolute}.

Source : WordNet®

involute
     adj 1: especially of petals or leaves in bud; having margins rolled
            inward [syn: {rolled}]
     2: (of some shells) closely coiled so that the axis is obscured