embryon.[F. embryon, Gr. 'e`mbryon, perh. fr. in (akin to L. E. in) + to be full of, swell with; perh. akin to E. brew.] (Biol.) The first rudiments of an organism, whether animal or plant()In embryo, in an incipient or undeveloped state; in conception, but not yet executed. The company little suspected what a noble work I had then in embryo. Swift.()a. Pertaining to an embryo; rudimentary; undeveloped; as, an embryo bud.()