The Collaborative International Dictionary of English v.0.48:

Fess \Fess\, Fesse \Fesse\, n. [OF. fesse, faisse, F. fasce, fr.
   L. fascia band. See Fascia.] (Her.)
   A band drawn horizontally across the center of an escutcheon,
   and containing in breadth the third part of it; one of the
   nine honorable ordinaries.
   [1913 Webster]

   Fess point (Her.), the exact center of the escutcheon. See
      Escutcheon.
      [1913 Webster]

WordNet (r) 3.0 (2006):

fess
    n 1: (heraldry) an ordinary consisting of a broad horizontal
         band across a shield [syn: fesse, fess]