miscegenation

Cohabitation, sexual relations, marriage, or interbreeding involving persons of different races, especially in historical contexts as a transgression of the law.

Mixture or amalgamation of races: applied especially to sexual union between individuals of the black and white races.

A mixing of races; amalgamation, as by intermarriage of black and white.

The mixing or blending of race in marriage or breeding, interracial marriage.

A mixing or blending, especially one which is considered to be inappropriate.

reproduction by parents of different races (especially by white and non-white persons)