"that part of the female animal in which eggs are generated," 1650s, from Modern Latin ovarium "ovary" (16c.), from Medieval Latin ovaria "the ovary of a bird" (13c.), from Latin ovum "egg," from PIE *ōwyo‑, *ōyyo‑ "egg," which is perhaps a derivative of the root *awi- "bird." In classical Latin, ovarius meant "egg-keeper," but Thomson ("Autumn") used ovarious (adj.) for "consisting of eggs."