foetus

Noun

fetus (plural fetuses or (hypercorrect) feti or (misconstruction) fetii)

1. (Australia, Canada, US, also) An unborn or unhatched vertebrate showing signs of the mature animal.
   • Several feti were removed from every rats' uterus, stripped of their membranes and allowed to lie in the peritoneal cavity connected to the placenta by the umbilical cord and with the placenta still attached to the uterine wall.1963, John W Choate, Henry A. Thiede, University of Rochester School of Medicine and Dentistry, Transcript, Volume 2
2. (Australia, Canada, US, also) A human embryo after the eighth week of gestation.
   • The sequence is: molecules in reproductive systems, then gametes, zygotes, morulas, blastocysts, and then fetuses.
3. (Australia, Canada, US, also, archaic) A neonate.
   • The real essence of that or any other sort of substances, it is evident, we know not; and therefore are so undetermined in our nominal essences, which we make ourselves, that, if several men were to be asked concerning some oddly-shaped fœtus, as soon as born, whether it were a man or no, it is...1959 [1689], John Locke, chapter 6, in An Essay Concerning Human Understanding, vol. 2, New York, N.Y.: Dover Publications, Inc., page 77