Source : Webster's Revised Unabridged Dictionary (1913)

Circumference \Cir*cum"fer*ence\, v. t.
   To include in a circular space; to bound. [Obs.] --Sir T.
   Browne.

Circumference \Cir*cum"fer*ence\, n. [L. circumferentia.]
   1. The line that goes round or encompasses a circular figure;
      a periphery. --Millon.

   2. A circle; anything circular.

            His ponderous shield . . . Behind him cast. The
            broad circumference Hung on his shoulders like the
            moon.                                 --Milton.

   3. The external surface of a sphere, or of any orbicular
      body.

Source : WordNet®

circumference
     n 1: the size of something as given by the distance around it
          [syn: {perimeter}]
     2: the length of the closed curve of a circle