Whirligig comes from Middle English whirlegigg, a compound of whirl ('to spin') + gig ('a spinning top, whirling thing'), denoting a spinning toy. In current use it is a noun meaning "a spinning toy or device, or something in constant whirling motion". That sense is explained by the older material without requiring a speculative semantic step: the inherited or borrowed base supplies the field of meaning, while the English formation fixes its modern role. The surface form is compositional: its joined elements remain visible in the modern word. The historical chain includes Old Norse hvirfla and Middle English gigg. Related English forms include whirl and gig. The word's history is thus visible in its construction: the components remain interpretable even after the whole expression has settled into a conventional English meaning.