The Collaborative International Dictionary
Superimpregnation
Superimpregnation \Su`per*im`preg*na"tion\, n. The act of impregnating, or the state of being impregnated, in addition to a prior impregnation; superfetation.
Wiktionary
superimpregnation
n. impregnation in addition to a prior impregnation; superfetation