Meaning

noun (botany) a minute rudimentary plant contained within a seed or an archegonium

noun 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

originBorrowed from Medieval Latin embryō, from Ancient Greek ἔμβρυον (émbruon, “fetus”), from ἐν (en, “in-”) + βρύω (brúō, “to grow, swell”).

Etymology from Wiktionary, CC BY-SA 3.0