1A plate of iron or other metal from which nails are cut; (as a mass noun) such metal plates collectively. Now rare.

2Anatomy and Zoology. The horny part of a fingernail or toenail; the horny wall of a claw.

3Surgery and Joinery. A perforated metal plate through which nails or screws can be inserted, used to join together two pieces of bone, timber, etc.