Source : Webster's Revised Unabridged Dictionary (1913)

Convolution \Con`vo*lu"tion\, n.
   1. The act of rolling anything upon itself, or one thing upon
      another; a winding motion.

            O'er the calm sea, in convolution swift, The
            feathered eddy floats.                --Thomson.

   2. The state of being rolled upon itself, or rolled or
      doubled together; a tortuous or sinuous winding or fold,
      as of something rolled or folded upon itself. --Blackmore.

   3. (Anat.) An irregular, tortuous folding of an organ or
      part; as, the convolutions of the intestines; the cerebral
      convolutions. See {Brain}.

Source : WordNet®

convolution
     n 1: the shape of something rotating rapidly [syn: {whirl}, {swirl},
           {vortex}]
     2: a convex fold or elevation in the surface of the brain [syn:
         {gyrus}]
     3: the action of coiling or twisting or winding together