Other forms: madams
Madam is a very formal way to address a woman, particularly an older or married woman. A waiter at a fancy restaurant might say, "Your table is ready, madam."
If a stranger calls a woman madam, he probably sees her as a mature, dignified person. If the woman is younger, she is more likely to be called "miss," and sometimes madam is abbreviated as "ma'am." Another kind of madam is a woman who owns or runs a house of prostitution. Madam comes from the French phrase ma dame, "my lady."