Medical Dictionary

embryo

noun em·bryo \ˈem-brē-ˌō\
plural em·bry·os

Medical Definition of EMBRYO

1
archaic :  a vertebrate at any stage of development prior to birth or hatching
2
:  an animal in the early stages of growth and differentiation that are characterized by cleavage, the laying down of fundamental tissues, and the formation of primitive organs and organ systems; especially :  the developing human individual from the time of implantation to the end of the eighth week after conception—compare fetus
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