other woman

other woman (plural other women)

1. (informal) A woman who is romantically involved with someone (usually a man) already in a committed relationship with another woman, especially a woman having an affair with a married man.

   Hypernym: home wrecker

   Coordinate term: other man

   Remembering the turmoil she experienced when her father left her mother, she vowed she would never be the other woman.

   • 1956, “The Other Woman”, Jessie Mae Robinson (lyrics)‎^[1]performed by Sarah Vaughan:

     The other woman finds time to manicure her nails / The other woman is perfect where her rival fails

• Almost always preceded by the definite article ("the").