ENGLISH
REFERENCE

fetus

n.
US //ˈfitəs// UK //fˈiːtəs// fe·tus
  1. 1 unborn animal (n.)
    C1 Advanced Technical Science

    an unborn or unhatched animal that has started to look like its adult form.

    an unborn or unhatched vertebrate that has developed beyond the embryo stage and shows the basic structural features of its species.

    Example

    The vet used an ultrasound to check if the horse's fetus was healthy.

    Example

    The researchers monitored the development of the whale fetus to understand how marine mammals adapt to deep-sea pressure before birth.
Origin

A learned borrowing from Latin fētus (“offspring”). Doublet of fawn.

Etymology adapted from Wiktionary, available under CC BY-SA 4.0.

Word family

Last updated June 20, 2026