Source : CEDICT

sb who is romantically involved with sb already in a committed relationship/the other woman/the other man/abbr. to 小三/third person/third party (in dispute)/disinterested party/number three in a list

Source : CEDICT

sb who is romantically involved with sb already in a committed relationship/the other woman/the other man/abbr. to 小三/third person/third party (in dispute)/disinterested party/number three in a list