- (botany) The production of two or more embryos in one seed, due either to the existence and fertilization of more than one embryonic sac or to the origination of embryos outside of the embryonic sac.
- (biology) The production of two or more embryos from a single fertilized egg.
2014, John C. Avise, Genetics in the Wild, ISBN 1588344290:
- One form of clonal reproduction begins when a fertilized egg divides a few times in the womb before initiating embryonic development. In humans, this can lead nine months later to the birth of identical (monozygotic) twins. This phenomenon, known as polyembryony, occurs sporadically in many mammal species. However, only in armadillos does polyembryony happen consistently, in each and every pregnancy.