cornerman

noun

1. A coach, trainer or other assistant who attends to a boxer between rounds.
2. A player who can play both the small forward and power forward positions.
3. (US, historical)A policeman assigned to an intersection to direct the traffic.

   “This cornerman is taking time out to provide directions to a driver. Their easily recognizable white hats and regular presence on their corners made these officers readily accessible […]”

4. Synonym of endman (“type of stock minstrel character”).