means The hard, flat plate of keratin growing at the tip of each toe, protecting the sensitive flesh beneath.

from A plain compound of "toe" and "nail," both ancient Germanic words. "Toe" descends from Old English "ta," a cousin of Dutch "teen" and German "Zehe." "Nail" comes from Old English "nægel," the same word that names the metal fastener — the two senses (the body's claw and the carpenter's spike) sat together in the Germanic languages from the start, both rooted in an old Proto-Indo-European term linked to claws and nails. So the foot's little plate has been called a "nail" for as long as English has been English.