bottleholder
nounEtymology From bottle (“from the bottle of water that is provided to the fighter”) + holder
1
Colloquial A person who attends a boxer during a bout.
2
Broadly, Colloquial One who assists or supports another in a contest; a backer.
- he has called me the bottle-holder of my right honourable friendOctober 17, 1796, John Philpot Curran, speech on Catholic Emancipation: