We don't have synonyms for placentation yet — it may be a rare, specialized, newly coined, or misspelled word. The closest thesaurus entries we have are plantation, lamentation and parentation.
(n) :
(biology) The local fusion of the embryonic stage of an animal to its parent for physiological exchange to promote the growth and development of the young; involves a placenta in non-egglaying mammals.
(n) :
(botany) The manner in which the seeds are attached to the placenta within the ovary locules.
(n) :
(biology) The local fusion of the embryonic stage of an animal to its parent for physiological exchange to promote the growth and development of the young; involves a placenta in non-egglaying mammals.
(n) :
(botany) The manner in which the seeds are attached to the placenta within the ovary locules.