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。
2Madam 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…