Where does “placenta” come from?

placenta (New Latin) comes from Latin placenta, from Ancient Greek πλακόεντα, from Ancient Greek πλακοῦς, from Ancient Greek πλακόεις, from Ancient Greek πλάξ, from Proto-Hellenic pləks, from Proto-Indo-European pleh₂- — flat.

placenta (New Latin): a vascular and endocrine organ; a round phyllo...