Armband (noun)

A band worn around the upper arm as a decoration or to indicate membership in a group or organization.

Origin:

A band worn around the arm, worn to indicate an affiliation or as a fashion accessory.

Examples:

1. He wore an armband to show his support for the team.
2. She wore an armband with a peace sign on it to the march.
3. The armband was a symbol of his rank in the organization.
4. The armband was worn by the team's captain.
5. The armband was made of a stretchy material for a comfortable fit.