noun pl. embryos -·os′

1. an animal in the earliest stages of its development in the uterus or the egg, specif., in humans, from conception to about the eighth week
2. 1. an early or undeveloped stage of something
   2. anything in such a stage
3. the rudimentary plant contained in a seed, usually made up of hypocotyl, radicle, plumule, and cotyledons

Etymology: ME embrio < ML embryo < Gr embryon, embryo, fetus, thing newly born, neut. of embryos, growing in < en-, in + bryein, to swell, be full

adjective