1 [C] (pluralbutterflies) an insect with a long, thin body and four brightly coloured wings 蝴蝶:
Caterpillars develop into butterflies.毛虫蜕变为蝴蝶。☞picture at insect 见 insect 插图
2 [U] a style of swimming in which both arms are brought over the head at the same time, and the legs move up and down together 蝶泳;蝶式
have butterflies (in your stomach)(informal 非正式) to feel very nervous before doing sth 行动之前忐忑不安