superfecundation

 
Pronunciation: /ˌsjuːpəfɛk(ə)nˈdeɪʃ(ə)n, -fiːk-, ˌsjuː-/

noun

[mass noun] Medicine & Zoology
  • fertilization of a second ovum during the same oestrus cycle as a result of a second mating, leading to fetuses of the same age but different parentage.