A crossbreed or crossbred usually refers to an organism with purebred parents of two different breeds, varieties, or populations. Crossbreeding, sometimes called "designer crossbreeding", refers to the process of breeding such an organism, often with the intention to create offspring that share the traits of both parent lineages, or producing an organism with hybrid vigor. While crossbreeding is used to maintain health and viability of organisms, irresponsible crossbreeding can also produce organisms of inferior quality or dilute a purebred gene pool to the point of extinction of a given breed of organism.
The term is also used at times to refer to a domestic animal of unknown ancestry where the breed status of only one parent or grandparent is known, though the term "mixed breed" is technically more accurate. The term outcross is used to describe a type of crossbreeding used within a purebred breed to increase the genetic diversity within the breed, particularly when there is a need to avoid inbreeding.
In animal breeding, crossbreed describes crosses within a single species, while hybrid refers to crosses between different species. In plant breeding terminology, the term crossbreed is uncommon. No universal term is used to distinguish hybridization or crossing within a population from those between populations, or even those between species.