pl.(mā-dă m′, -d\u00e4m′) Used formerly as a courtesy title before a woman's given name but now used only before a surname or title indicating rank or office: Madam Ambassador. Used as a salutation in a letter: Dear Madam or Sir. Used as a form of polite address for a woman: Right this way, madam. The mistress of a household. A woman who manages a brothel.