Chapeau

from WordNet (r) 3.0 (2006)

chapeau
    n 1: headdress that protects the head from bad weather; has
         shaped crown and usually a brim [syn: {hat}, {chapeau},
         {lid}]

from The Collaborative International Dictionary of English v.0.48

Chapeau \Cha`peau"\, n.; pl. {Chapeux}. [F., fr. OF. chapel hat.
   See {Chaplet}.]
   1. A hat or covering for the head.
      [1913 Webster]

   2. (Her.) A cap of maintenance. See {Maintenance}.
      [1913 Webster]

   {Chapeau bras}[F. chapeau hat + bras arm], a hat so made that
      it can be compressed and carried under the arm without
      injury. Such hats were particularly worn on dress
      occasions by gentlemen in the 18th century. A chapeau bras
      is now worn in the United States army by general and staff
      officers.
      [1913 Webster]