Source : Webster's Revised Unabridged Dictionary (1913)

Swirl \Swirl\, v. t. & i. [imp. & p. p. {Swirled}; p. pr. & vb.
   n. {Swirling}.] [Akin to Norw. svirla to whirl, freq. of
   sverra to whirl, Dan. svirre, G. schwirren to whiz, to buzz.
   [root]177. See {Swarm}, n.]
   To whirl, or cause to whirl, as in an eddy. ``The river
   swirled along.'' --C. Kingsley.

Swirl \Swirl\, n.
   A whirling motion; an eddy, as of water; a whirl. ``The
   silent swirl of bats.'' --Mrs. Browning.

Source : WordNet®

swirl
     n : the shape of something rotating rapidly [syn: {whirl}, {vortex},
          {convolution}]
     v 1: turn in a twisting or spinning motion; "The leaves swirled
          in the autumn wind" [syn: {twirl}, {twiddle}, {whirl}]
     2: flow in a circular current, of liquids [syn: {eddy}, {purl},
         {whirlpool}, {whirl}]