Definition of placentation in English:



mass noun
  • 1Anatomy Zoology
    The 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.’
    • ‘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.’
    • ‘Most embryo clones fail to develop, and pregnancies terminate spontaneously due to fetal abnormalities or difficulties with placentation.’
    • ‘Functional roles for relaxin within human reproductive tissues have also been implicated during placentation, parturition, and lactation.’
    • ‘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.’
    1. 1.1Botany The arrangement of the placenta or placentae in the ovary of a flower.
      • ‘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.’
      • ‘These are distinguished by characters of the bracts, placentation, inflorescence type, cytology and distribution.’
      • ‘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.’
      • ‘Salicornioideae seeds have a basal placentation, congruent with other representatives of the Chenopodiaceae.’