The children were fascinated by the spinning whirligigs in the garden.

whirligigs 是 whirligig 的复数形式。这个词由 whirl（旋转）和 gig（小玩具）组成，字面意思是"旋转的小玩具"，指一种会旋转的玩具，比如陀螺或风车玩具。