The Collaborative International Dictionary of English v.0.48:

Enceinte \En`ceinte"\, n. [F., fr. enceindre to gird about,
   surround, L. incingere; in (intens). + cingere to gird. See
   Cincture.]
   1. (Fort.) The line of works which forms the main inclosure
      of a fortress or place; -- called also body of the
      place.
      [1913 Webster]

   2. The area or town inclosed by a line of fortification.
      [1913 Webster]

            The suburbs are not unfrequently larger than their
            enceinte.                             --S. W.
                                                  Williams.
      [1913 Webster]