Definition from Wiktionary, the free dictionary
superfetation (plural superfetations)
- An excessive accumulation; a superfluous addition.
- 1857: These gentlemen were greatly astonished at Bovary's romantic ideas, and the pharmacist hurried in to say to him: "This velvet looks to me rather a superfetation. Besides, the expense..." — Gustave Flaubert, Madame Bovary (tr. Geoffrey Wall 1992).
- The formation of a fetus while another fetus is already present in the uterus.