Madam

n. pl. Madams, or Mesdames (#).

1. A gentlewoman; -- an appellation or courteous form of address given to a lady, especially an elderly or a married lady; -- much used in the address, at the beginning of a letter, to a woman. The corresponding word in addressing a man is Sir; often abbreviated ma'am when used as a term of address.
2. The woman who is in charge of a household.
3. The woman who is in charge of a brothel.