Source : Webster's Revised Unabridged Dictionary (1913)

Polka \Pol"ka\, n. [Pol. Polka a Polish woman: cf. F. & G.
   polka.]
   1. A dance of Polish origin, but now common everywhere. It is
      performed by two persons in common time.

   2. (Mus.) A lively Bohemian or Polish dance tune in 2-4
      measure, with the third quaver accented.

   {Polka jacket}, a kind of knit jacket worn by women.