Definition of watermen:
(n) :
A man who lives or works on the water; a boatman.
(n) :
Someone who distributes or supplies water for a living; a water-carrier.
(n) :
(surfing) A man skilled in multiple aquatic sports disciplines, such as surfing, bodysurfing, undersea diving, canoe paddling, fishing, etc.
(n) :
(dated) Specifically, an attendant on cab stands who supplies water to the horses.
(n) :
(obsolete) A seaman, a sailor.
(n) :
An occupational surname.