Webster’s Revised Unabridged Dictionary · 1913
Madam
Mad′am (măd′am), n.; pl. Madams, or Mesdames (#). [See Madame.] 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.