1 (formal 正式) used as a polite way of speaking to a woman, especially to a customer in a shop or restaurant 女士，太太（对妇女的礼貌称呼，尤用于招呼顾客）: Can I help you, madam? 太太，你想要买些什么？ ☞ Look at sir. 参看sir。

2 Madam used for beginning a formal letter to a woman when you do not know her name （用于正式信函的开头，以称呼不知姓名的妇女）: Dear Madam, I am writing in reply... 敬启者：现谨就…回复…