Cornerman

A cornerman, or simply corner, is a combat sports term for a coach or teammate assisting a fighter during the length of a bout. The cornerman remains outside the combat area during the fight, but in proximity, and can assist the fighter through instruction. This instruction can take place in between rounds, as in boxing.

The cornerman occasionally performs cutman duties such as applying ice to reduce swelling and stopping bleeding. The cornerman may also be responsible for throwing in the towel when necessary.

In boxing, cornermen are called seconds, the term also applicable to the assistants of participants in a duel.

...
Wikipedia