• Webster's Revised Unabridged Dictionary
    • a Metadiscoidal (Anat) Discoidal by derivation; -- applied especially to the placenta of man and apes, because it is supposed to have been derived from a diffused placenta.
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Century Dictionary and Cyclopedia
    • metadiscoidal In embryology, noting the placenta of certain mammals such as the primates (man and apes), in which the villi are restricted to a disk-shaped chorionic area on the ventral side of the embryo.
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Webster's Revised Unabridged Dictionary
Meta-, + discoidal,