whirl·i·gig / ˈ(h)wərlēˌgig/ • n. 1. a toy that spins around, for example a top or windmill. ∎ another term for merry-go-round. 2. [in sing.] a thing regarded as hectic or constantly changing: the whirligig of time. 3. (also whirligig beetle) a small black predatory beetle (Gyrinus and other genera, family Gyrinidae) that swims rapidly in circles on the surface of still or slow-moving water and dives when alarmed.

whirligig beetle See GYRINIDAE.