agraffe

noun

1. A clasp consisting of a hook which fastens onto a ring.

   “The feather of an ostrich, fastened in her turban by an agraffe set with brilliants, was another distinction of the beautiful Jewess, scoffed and sneered at by the proud dames who sat above her, but secretly envied by those who affected to deride them.”

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.