The Collaborative International Dictionary of English v.0.48:

Punka \Pun"ka\, n. [Hind. pankh[=a] fan.]
   A machine for fanning a room, usually a movable fanlike frame
   covered with canvas, and suspended from the ceiling. It is
   kept in motion by pulling a cord. [Hindostan] [Written also
   punkah.] --Malcom.
   [1913 Webster]