📒 a person's (usually a married man’s) mistress is a woman that they have a regular sexual relationship with and who is not their wife
📒 a female teacher in a school, especially a private school
📒 (in the past) the female head of a house, especially one who employed servants
📒 the female owner of a dog or other animal
📒 a woman who is in a position of authority or control, or who has a lot of skill in something