'Placental' definitions:

Definition of 'placental'

(from WordNet)
adjective
Pertaining to or having or occurring by means of a placenta; "all mammals except monotremes and marsupials are placental mammals" [ant: aplacental]
noun
Mammals having a placenta; all mammals except monotremes and marsupials [syn: placental, placental mammal, eutherian, eutherian mammal]

Definition of 'Placental'

From: GCIDE
  • Placental \Pla*cen"tal\, a.
  • 1. Of or pertaining to the placenta; having, or characterized by having, a placenta; as, a placental mammal. [1913 Webster]
  • 2. (Zool.) Of or pertaining to the Placentalia. [1913 Webster]

Definition of 'Placental'

From: GCIDE
  • Placental \Pla*cen"tal\, n. (Zool.) One of the Placentalia. [1913 Webster]