noun. 1. the mating of human beings who are not related or who stem from varied groups. It is hence the opposite of inbreeding. 2. the mating of an animal with another which is not related or a distantly related animal of the same species. This might generate hybrid vigor. Commonly referred to as cross-breeding.

OUTBREEDING: "Outbreeding isn't typically referenced because It is considered to be the norm in American society."