(medicine, obstetrics) A fetus growing inside the body of another fetus, either from an unsuccessful twin pregnancy, or as a tumorlike growth.

(Australia, Canada, US) An unborn or unhatched vertebrate showing signs of the mature animal. / (Australia, Canada, US) A human embryo after the eighth week of gestation.

(Canada, US, politics, derogatory) One who supports fetal rights; an antiabortionist.

plural of fetus fetishist

A vanishing twin that, rather than being completely reabsorbed, is compressed by its growing twin to a flattened, parchment-like condition.

plural of fetus in fetu

plural of fetus