The Collaborative International Dictionary of English v.0.48:

kepi \kep"i\, n. [F. k['e]pi, of G. origin.]
   A military cap having a close-fitting band, a round flat top
   sloping toward the front, and a visor. As originally worn by
   the French in Algeria about 1830 it was tall and stiff with a
   straight visor. It is now lower, has a curved visor, and is
   frequently soft.

   Syn: peaked cap, service cap, yachting cap.
        [Webster 1913 Suppl.]

WordNet (r) 3.0 (2006):

kepi
    n 1: a cap with a flat circular top and a visor [syn: kepi,
         peaked cap, service cap, yachting cap]