I was watching an episode of What's My Line? aired some time in the 1950s. A female guest signed in and host John Daly asked "Is it Miss or Mrs.?"
I watched with the Closed Captioning on, and the CC typist decided to spell it rather than use an abbreviation, so we got "Is it Miss or Misses?"
Misses? Daly wasn't asking if she was one or more than one unmarried young woman.
It's spelled "missus," though I suppose you don't see it that much in print these days. Perhaps the typist was too young to know.