In biology, hybrid has three meanings.

The first meaning is of crosses between two animals or plants of different taxa. Hybrids between different species within the same genus are sometimes known as interspecific hybrids or crosses. Hybrids between different sub-species within a species are known as intra-specific hybrids. Hybrids between different genera are sometimes known as intergeneric hybrids.

The second meaning of "hybrid" is crosses between populations, breeds or cultivars of a single species. This second meaning is often used in plant and animal breeding.