Fertilization of a second ovum after a pregnancy has begun; results in two fetuses of different ages in the uterus at the same time.

Roget 37: addition, annexation, adjection^†; junction etc. 43; superposition, superaddition, superjunction^†, superfetation; accession, reinforcement; increase etc. 35; increment, supplement; accompaniment etc. 88; interposition etc. 228; insertion etc. 300.    ... show more

Roget 168: productiveness etc. adj.; fecundity, fertility, luxuriance, uberty^†.    pregnancy, pullulation, fructification, multiplication, propagation, procreation; superfetation.    milch cow, rabbit, hydra, warren, seed plot, land flowing with milk and honey; second crop, aftermath; aftercrop, aftergrowth^†; arrish^†, eddish^†, rowen^†; protoplasm; fertilization.    ... show more