1N-COUNT 蝴蝶 A butterfly is an insect with large colourful wings and a thin body. 蝴蝶
2N-UNCOUNT [oft theNOUN]蝶泳Butterfly is a swimming stroke which you do lying on your front, kicking your legs and bringing your arms over your head together. 蝶泳
3PHRASE 情绪紧张;心慌意乱;忐忑不安 If you have butterflies in your stomach or have butterflies, you are very nervous or excited about something. 情绪紧张;心慌意乱;忐忑不安 [informal]
An exam, or even an exciting social event may produce butterflies in the stomach.