Source : Webster's Revised Unabridged Dictionary (1913)

Hat \Hat\, n. [AS. h[ae]t, h[ae]tt; akin to Dan. hat, Sw. hatt,
   Icel. hattr a hat, h["o]ttr hood, D. hoed hat, G. hut, OHG.
   huot, and prob. to L. cassis helmet. ???. Cf.{Hood}.]
   A covering for the head; esp., one with a crown and brim,
   made of various materials, and worn by men or women for
   protecting the head from the sun or weather, or for ornament.

   {Hat block}, a block on which hats are formed or dressed.

   {To pass around the hat}, to take up a collection of
      voluntary contributions, which are often received in a
      hat. [Collog.] --Lowell.