mistress

noun

• 1a woman in a position of authority or control:she is always mistress of the situation, coolly self-possessed
• [with modifier] British a female schoolteacher who teaches a particular subject:a Geography mistress
• a woman who is skilled in a particular subject or activity:a mistress of the sound bite, she is famed for the acidity of her tongue
• the female owner of a dog, cat, or other domesticated animal: the cat rubbed itself against its mistress’s legs
• archaic a female head of a household:he asked for the mistress of the house
• (especially formerly) a female employer of domestic staff: Mary, go and fetch your mistress some cold chicken

• 2a woman (other than the man’s wife) having a sexual relationship with a married man: Elsie knew her husband had a mistress tucked away somewhere
• archaic or literary a woman loved and courted by a man.

• 3 (Mistress) archaic or dialect used as a title prefixed to the name of a married woman; Mrs.