Definition of placentation in US English:

placentation

noun

Zoology Anatomy
  • 1The formation or arrangement of a placenta or placentae in a woman's or female animal's uterus.

    • ‘The presence of an apparently unique type of lymphocyte in the uterus at implantation and during early placentation is intriguing.’
    • ‘Functional roles for relaxin within human reproductive tissues have also been implicated during placentation, parturition, and lactation.’
    • ‘Most embryo clones fail to develop, and pregnancies terminate spontaneously due to fetal abnormalities or difficulties with placentation.’
    • ‘Notably, in the three mammalian groups, equids, murids, and peromyscids, in which placental development of interspecific hybrids was analyzed to date, placentation defects were observed.’
    • ‘Although the exact etiology for placenta accreta and increta is not known, it is thought that damage to the decidua basalis may lead to abnormal placentation and its sequelae.’
    1. 1.1Botany The arrangement of the placenta or placentae in the ovary of a flower.
      • ‘These are distinguished by characters of the bracts, placentation, inflorescence type, cytology and distribution.’
      • ‘Salicornioideae seeds have a basal placentation, congruent with other representatives of the Chenopodiaceae.’
      • ‘The berries in the most derived clade (Olmstead et al.'s subfamily ‘Solanoideae’) are all morphologically similar, with two carpels, axile placentation and mostly lenticular seeds.’
      • ‘The ovary is superiorly positioned with basal placentation.’
      • ‘Both genera were transferred to Flacourtiaceae by Warburg and later by Gilg on the basis of a number of morphological characters, such as a trimerous ovary with parietal placentation and anthers with longitudinal dehiscence.’

Pronunciation

placentation

/ˌplas(ə)nˈtāSH(ə)n/