Butterflies in one's stomach

Origin

The universal experience of nervous excitement manifesting as a churning in the gut finally found its perfect metaphor in the early 20th century. Before this, the sensation was often described as a 'sinking' or 'queasy' feeling. But it was the evocative image of 'butterflies'—delicate, restless, and unpredictable—that truly captured the light, fluttering chaos within. This vivid imagery, perhaps first taking hold in the informal speech of early 20th-century America, quickly painted a picture in the mind's eye that perfectly articulated the physical sensation of anticipation, fear, or exhilaration, forever linking a biological response to the graceful, yet unsettling, flight of insects.