The Collaborative International Dictionary of English v.0.48:

Turbot \Tur"bot\, n. [F.; -- probably so named from its shape,
   and from L. turbo a top, a whirl.] (Zool.)
   (a) A large European flounder (Rhombus maximus) highly
       esteemed as a food fish. It often weighs from thirty to
       forty pounds. Its color on the upper side is brownish
       with small roundish tubercles scattered over the surface.
       The lower, or blind, side is white. Called also bannock
       fluke.
   (b) Any one of numerous species of flounders more or less
       related to the true turbots, as the American plaice, or
       summer flounder (see Flounder), the halibut, and the
       diamond flounder (Hypsopsetta guttulata) of California.
   (c) The filefish; -- so called in Bermuda.
   (d) The trigger fish.
       [1913 Webster]

   Spotted turbot. See Windowpane.
      [1913 Webster]