Fertilization of two or more ova released in the same period of ovulation, either by different males or by the same male in separate acts of intercourse.
Note: If there are two or more different fathers, the state may be called heteropaternal superfecundation. Rare in humans, heteropaternal superfecundation is common in some species, such as cats and dogs.
Source:
PAC, 2016, 88, 713. 'Glossary of terms used in developmental and reproductive toxicology (IUPAC Recommendations 2016)' on page 809 (https://doi.org/10.1515/pac-2015-1202)