: 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
b
archaic: a vertebrate at any stage of development prior to birth or hatching
2
: the young sporophyte of a seed plant usually comprising a rudimentary plant with plumule, radicle, and cotyledons
3
a
: something as yet undeveloped
b
: a beginning or undeveloped state of something
… productions seen in embryo during their out-of-town tryout period …—Henry Hewes
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