madam
n. countablen. a polite and formal way to speak to a woman you do not know. You often hear this in shops or restaurants when staff are being very respectful.
n. a formal and polite term of address for a woman, typically used by service staff or in formal correspondence. Often functions as the female equivalent of 'sir'.
May I take your coat, madam?
The waiter bowed slightly and asked if madam was ready to order her main course.
In formal business correspondence where the recipient's name is unknown, the salutation 'Dear Madam' remains a standard, albeit increasingly traditional, opening.
From Middle English madame, from Old French madame, from ma (“my”) + dame (“lady”), from post-classical Latin mea domina. Doublet of Madonna.
Commonly used in the vocative case to address a customer or superior; in British English, it can also describe a precocious or bossy young girl.