/ ˈɑːmbænd; NAmE ˈɑːrm-/ noun
1.
a cloth band worn around the arm as a sign of sth, for example that sb has an official position :
The stewards all wore armbands.
Many people at the funeral service were wearing black armbands.
2.
either of two plastic rings that can be filled with air and worn around the arms by sb who is learning to swim