• WordNet 3.6
    • n superfetation fertilization of a second ovum after a pregnancy has begun; results in two fetuses of different ages in the uterus at the same time "superfetation is normal in some animal species"
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Webster's Revised Unabridged Dictionary
    • n Superfetation (Physiol) The formation of a fetus at the result of an impregnation occurring after another impregnation but before the birth of the offspring produced by it. This is possible only when there is a double uterus, or where menstruation persists up to the time of the second impregnation. "In then became a superfetation upon, and not an ingredient in, the national character."
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Century Dictionary and Cyclopedia
    • n superfetation A second conception some time after a prior one, by which two fetuses of different age exist together in the same female: often used figuratively. The possibility of superfetation in the human female has been the subject of much investigation, but the weight of evidence goes to show that it may occur not only with double uteri, but also in the earlier period of pregnancy, under rare conditions, with normal single uterus. Also called superconception.
    • n superfetation The fetus produced by superfetation; hence, any excrescent growth.
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Webster's Revised Unabridged Dictionary
Cf. F. superfétation,


In literature:

Marcellus Donatus, Goret, Schacher, and Mauriceau mention superfetation.
"Anomalies and Curiosities of Medicine" by George M. Gould
He became the victim of a sort of intellectual superfetation.
"Art in England" by Dutton Cook