The Collaborative International Dictionary of English v.0.48:

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.
      [1913 Webster]

   2. (Zool.)
      (a) Turned inward at the margin, as the exterior lip of
          the Cyprea.
      (b) Rolled inward spirally.
          [1913 Webster]

The Collaborative International Dictionary of English v.0.48:

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.
   [1913 Webster]

WordNet (r) 3.0 (2006):

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