People sometimes say Madam as a very formal and polite way of addressing a woman whose name they do not know or a woman of superior rank. For example, a shop assistant might address a woman customer as Madam. [politeness]

You use the expression ' Dear madam' at the beginning of a formal or business letter or email when you are writing to a woman.

Madam is sometimes used in front of words such as ' Chairman' to address the woman who holds the position mentioned.

You can call a little girl a madam if you are annoyed because she is being naughty and behaving as if she expects other people to do what she wants. [mainly British, spoken, disapproval]