n, pl  em*bry*os  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 : esp  :  the developing human individual from the time of implantation to the end of the eighth week after conception - compare FETUS  .
 
 
 
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