Source : Webster's Revised Unabridged Dictionary (1913)

Annulet \An"nu*let\, n. [Dim. of annulus.]
   1. A little ring. --Tennyson.

   2. (Arch.) A small, flat fillet, encircling a column, etc.,
      used by itself, or with other moldings. It is used,
      several times repeated, under the Doric capital.

   3. (Her.) A little circle borne as a charge.

   4. (Zo["o]l.) A narrow circle of some distinct color on a
      surface or round an organ.

Source : WordNet®

annulet
     n 1: a charge in the shape of a circle; a hollow roundel [syn: {roundel}]
     2: molding in the form of a ring; at top of a column [syn: {bandelet},
         {bandelette}, {bandlet}, {square and rabbet}]
     3: a small ring