the horny scale of plate of epidermis at the end of the fingers and toes of man and many apes.-the basal thickened portion of the anterior wings of certain hemiptera.-the terminal horny plate on the beak of ducks, and other allied birds.-a slender, pointed piece of metal, usually with a head, used for fastening pieces of wood or other material together, by being driven into or through them.-a measure of length, being two inches and a quarter, or the sixteenth of a yard.-to fasten with a nail or nails; to close up or secure by means of nails; as, to nail boards to the beams.-to stud or boss with nails, or as with nails.-to fasten, as with a nail; to bind or hold, as to a bargain or to acquiescence in an argument or assertion; hence, to catch; to trap.-to spike, as a cannon.