Definition of plumbers:
(n) :
One who furnishes, fits, and repairs pipes and other apparatus for the conveyance of water, gas, or drainage.
(n) :
One who installs piping for potable and waste water.
(n) :
(dated) One who works in or with lead.
(n) :
A person who investigates or prevents leaks of information.
(n) :
(slang, medicine, somewhat derogatory) A urologist.
(n) :
(British, informal) In the Royal Navy, an apprentice, a boy aged 16 to 18, who is trained in technical skills at the Dockyard Schools to become an artificer.