Source : Webster's Revised Unabridged Dictionary (1913)

Whirligig \Whirl"i*gig\, n. [Whirl + gig.]
   1. A child's toy, spun or whirled around like a wheel upon an
      axis, or like a top. --Johnson.

   2. Anything which whirls around, or in which persons or
      things are whirled about, as a frame with seats or wooden
      horses.

            With a whirligig of jubilant mosquitoes spinning
            about each head.                      --G. W. Cable.

   3. A medi[ae]val instrument for punishing petty offenders,
      being a kind of wooden cage turning on a pivot, in which
      the offender was whirled round with great velocity.

   4. (Zo["o]l.) Any one of numerous species of beetles
      belonging to {Gyrinus} and allied genera. The body is
      firm, oval or boatlike in form, and usually dark colored
      with a bronzelike luster. These beetles live mostly on the
      surface of water, and move about with great celerity in a
      gyrating, or circular, manner, but they are also able to
      dive and swim rapidly. The larva is aquatic. Called also
      {weaver}, {whirlwig}, and {whirlwig beetle}.

Source : WordNet®

whirligig
     n 1: a conical child's plaything tapering to a steel point on
          which it can be made to spin; "he got a bright red top
          and string for his birthday" [syn: {top}, {teetotum}, {spinning
          top}]
     2: large mechanical apparatus with seats for children to ride
        on [syn: {carousel}, {carrousel}, {merry-go-round}, {roundabout}]
     v : whirl or spin like a whirligig