Superimpregnation

Part of speech: noun

Definitions

1. Fertilization of a female animal that is already carrying young, so that embryos of different ages develop together
2. The act of conceiving additional offspring while an existing pregnancy is still underway, sometimes by a different male
3. Second conception occurring during an ongoing gestation, producing fetuses at differing stages of development in one female

Etymology: Superimpregnation is a compound formed from the prefix "super-", meaning "over" or "above" in the sense of "in addition to", and "impregnation". The second element comes from the Latin "impraegnare", "to make pregnant", built from "in-" and "praegnans", the source of English "pregnant". The prefix "super-" comes from Latin "super", "above" or "over", which has long been used in English to indicate excess or something extra. The word describes a rare event in which a second conception occurs during an existing pregnancy, so that the two embryos are fertilised at different times. The compound is a transparent, technical formation: its meaning follows directly from its two parts, and the term is used mainly in medical and biological writing where the phenomenon needs a precise name.