noun

• (British) Usually capitalized as Dame: a title equivalent to Sir for a female knight.
  "Dame Edith Sitwell"
• (British) A matron at a school, especially Eton College.
  "Even though the dames’ houses were being gradually phased out at Eton, [John Henry] Newman was enthusiastic about the arrangement since it met one of the promoters’ key demands; besides, he had experienced something similar as a boy at Ealing School, where the boarding houses were also under the jurisdiction of dames. The Ealing dames ensured that boys were properly dressed and cared for them when sick, and they also ran the tuck shops."
• (British, theater) In traditional pantomime: a melodramatic female often played by a man in drag.
  "[page 73, column 2] Mother Goose was produced on the 29th of December; Simmons playing the Old Dame; […] [page 74, column 1] Bugle condemns her to the ducking-stool, a sentence opposed by Colin, who espouses the cause of the Old Dame, who, escaping from her persecutors, puts an end to the wedding festivities by raising the ghost of the Squire's first wife."
• (US, dated, informal, slightly derogatory) A woman.
  "I can see that would be the kind of a chap that the dames would stand for everlastingly."

noun

• (British) The titular prefix given to a female knight