Source : Webster's Revised Unabridged Dictionary (1913)

Glengarry \Glen*gar"ry\, n., or Glengarry bonnet \Glen*gar"ry
bon"net\ [Name of a valley in Scotland.]
   A kind of Highland Scotch cap for men, with straight sides
   and a hollow top sloping to the back, where it is parted and
   held together by ribbons or strings.

         The long silk streamers of his Glengarry bonnet. --L.
                                                  Hutton.