large ornament with a pin fastening

A brooch is a piece of jewelry that is attached to clothes. It is usually made of metal, silver or gold but sometimes bronze and decorated with gemstones.

Braganza Fibula/Brooch, Hellenistic art, 250-200 BC, British Museum

Brooches called "fibulae" were used for many centuries to fasten clothing. In recent centuries people more often use buttons and belts for that, so brooches have become only decorative.