Definition of "placental"

placental

adjective
not comparable
1. Of or pertaining to the placenta.
2. (zoology) Pertaining to the Placentalia, comprising those mammals not marsupials or monotremes.
  Quotations
  We do not know exactly how many placental lineages survived to leave descendants; most estimates are around ten.
  2022, Thomas Halliday, Otherlands, Penguin, published 2023, page 103
noun
plural placentals
1. Any animal that is a member of the Placentalia