屁股在英语中被称为 "butt" 或 "buttocks"。这个词来自古英语 "butan"，意思是 "肌肉、组织"。

例句：

She has a nice butt. 她的屁股很好看。

He has been hitting the gym, and you can really see it in his butt. 他一直在健身房锻炼，你能从他的屁股看出来。

He fell on his butt and scraped his knees. 他摔倒了，屁股和膝盖都擦伤了。