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

a vertebrate at any stage of development prior to birth or hatching

the young sporophyte of a seed plant usually comprising a rudimentary plant with plumule, radicle, and cotyledons