plant vs embryo

plant and embryo both are nouns.

As nouns, embryo is a hyponym of plant; that is, embryo is a word with a more specific, narrower meaning than plant:

plant: (botany) a living organism lacking the power of locomotion
embryo: (botany) a minute rudimentary plant contained within a seed or an archegonium

Other hyponyms of plant include microflora, crop, endemic, holophyte, non-flowering plant, plantlet, wilding, ornamental, pot plant, acrogen, apomict, aquatic, cryptogam, annual, biennial, perennial, escape, hygrophyte, neophyte, monocarp, monocarpic plant, monocarpous plant, sporophyte, gametophyte, houseplant, garden plant, vascular plant, tracheophyte, poisonous plant, epiphyte, epiphytic plant, aerophyte, air plant, rock plant, autophyte, autophytic plant, autotroph, autotrophic organism, myrmecophyte, phytoplankton.

plant (noun)	embryo (noun)
buildings for carrying on industrial labor	(botany) a minute rudimentary plant contained within a seed or an archegonium
(botany) a living organism lacking the power of locomotion	an animal organism in the early stages of growth and differentiation that in higher forms merge into fetal stages but in lower forms terminate in commencement of larval life
an actor situated in the audience whose acting is rehearsed but seems spontaneous to the audience
something planted secretly for discovery by another

plant (verb)	embryo (verb)
put or set (seeds, seedlings, or plants) into the ground
fix or set securely or deeply
set up or lay the groundwork for
place into a river
place something or someone in a certain position in order to secretly observe or deceive
put firmly in the mind