mem-sahib (n.)

also maam, 1660s, colloquial shortening of madam (q.v.). At one time the ordinary respectful form of address to a married woman; later restricted to the queen and royal princesses or used by servants to their mistresses. In U.S., used especially in answers, after yes or no.

"gentleman, sir," respectful address to Europeans in India, 1670s, from Hindi or Urdu sahib "master, lord," from Arabic sahib, originally "friend, companion," from sahiba "he accompanied." Female form ("European lady") is memsahib.