腋

例句：

1. 1. She wore a sleeveless dress that exposed her armpit.
   她穿着一件露肩连衣裙，露出了她的腋下。
2. 2.The doctor advised him to keep his armpit clean and dry.
   医生建议他保持腋下干净干燥。
3. 3.He rubbed his armpits vigorously to relieve the itching.
   他用力揉搓腋下来缓解瘙痒。