What is an "armband"?

An armband is a strip of cloth, plastic, or other material worn around the upper arm, often for identification purposes or to signify membership in a particular group or organization. Armbands can also be used in sports, such as to indicate a team or position, or in military contexts, where they can be used to identify a soldier's rank or unit. They are sometimes worn as a fashion accessory or to hold a smartphone during exercise. Some armbands have pockets or other features for storing small items.