/fee"teuhs/ , n. , pl. fetuses . Embryol.
(used chiefly of viviparous mammals) the young of an animal in the womb or egg, esp. in the later stages of development when the body structures are in the recognizable form of its kind, in humans after the end of the second month of gestation.
Also, esp. Brit., foetus . Cf. embryo (def. 2).
[ 1350-1400; ME fetus bringing forth of young, hence that which is born, offspring, young still in the womb, equiv. to fe- (v. base attested in L only in n. derivatives, as femina woman, fecundus FECUND, etc.; cf. Gk thesthai to suck, milk, OHG taan to suck, OIr denid (he) sucks) + -tus suffix of v. action ]