mistress

a woman who is having a sexual relationship with someone who is married to another person

amante, amiga íntima (en un contexto amoroso)

• have a mistress

Collocations a married man's mistress

• He has been seeing his mistress for years.

  Ha estado viendo a su amante durante años.

a woman who teaches in a school, especially one that is run by a religious organization

maestra, profesora (en un colegio)

• be a mistress at/in

Collocations a strict mistress

• She was the mistress of the school for many years.

  Ella fue la maestra del colegio durante muchos años.

a woman who owns or manages a house, hotel, or business

dueña, propietaria (de una casa o negocio)

• be the mistress of

Collocations the mistress of a large house

• She is the mistress of this grand hotel.

  Ella es la dueña de este gran hotel.