Hatband (noun)

1. A strip of material, often leather, used to hold a hat in place or to add decoration.
2. A decorative band, often made of leather or ribbon, worn around the base of a hat, serving to hold it in place and/or as a decorative element.

Origin:

Hat + band.

Examples:

1. He wore a black hat with a silver hatband.
2. The hatband was made of leather and had a silver buckle.
3. The hatband was decorated with a feather.
4. The hatband was a sign of the wearer's social status.
5. He changed the hatband to match his outfit.