ARMBAND

[noun] [C] - a piece of material that a person wears around the arm as a sign of something, for example an official positionAll the stewards at the racetrack were wearing armbands.People sometimes wear black armbands to show to show that a friend or relative has died.An armband is also a hollow ring-shaped piece of plastic, into which you blow air, which children who cannot swim wear on their arms in water, in order to help them float.