https://doi.org/10.1351/goldbook.11267
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.