Noun | 1. | ![]() conceptus, fertilized egg, embryo - an animal organism in the early stages of growth and differentiation that in higher forms merge into fetal stages but in lower forms terminate in commencement of larval life fetus, foetus - an unborn or unhatched vertebrate in the later stages of development showing the main recognizable features of the mature animal duct, epithelial duct, canal, channel - a bodily passage or tube lined with epithelial cells and conveying a secretion or other substance; "the tear duct was obstructed"; "the alimentary canal"; "poison is released through a channel in the snake's fangs" funiculus - any of several body structure resembling a cord fetal membrane - any membrane that functions for the protection or nourishment or respiration or excretion of a developing fetus umbilical vein, vena umbilicalis - a vein in the umbilical cord; returns nutrient blood from the placenta to the fetus |