nail

(noun): The thin, horny plate at the ends of fingers and toes on humans and some other animals.
(noun): The basal thickened portion of the anterior wings of certain hemiptera.
(noun): The terminal horny plate on the beak of ducks, and other allied birds.
(noun): The claw of a bird or other animal.
(noun): A spike-shaped metal fastener used for joining wood or similar materials. The nail is generally driven through two or more layers of material by means of impacts from a hammer or other device. It is then held in place by friction.
(noun): A round pedestal on which merchants once carried out their business, such as the four nails outside The Exchange, Bristol.
(noun): An archaic English unit of length equivalent to 1/20 of an ell or 1/16 of a yard (2 1/4 inches or 5.715 cm).