Agraffe

Noun

1. A clasp consisting of a hook which fastens onto a ring.
2. A hook, eyelet, or other device by which a piano wire is held so as to limit the vibration.
3. A carved keystone, usually decorated with a mascaron or a corbel, often used in Classical architecture.
4. A brass fitting, screwed into a piano plate, that positions the strings vertically and laterally, and defines one end of the string's speaking length.