An embryo (irregularly from Greek: ', plural ', lit. "that which grows," from en- "in" + bryein "to swell, be full"; the proper Latinate form would be embryum) is a multicellular diploid eukaryote in its earliest stage of development, from the time of first cell division until birth, hatching, or germination. In humans, it's called an embryo until about eight weeks after fertilization (for example ten weeks LMP), and from then it's instead called a fetus. Development The development of the embr… (More on Embryos)