means A tradesperson who installs and repairs the pipes, drains, and fixtures that carry water and waste through your home.

from Straight from the Latin 'plumbum,' meaning lead — the soft, heavy metal Roman pipes were made from (it's also why lead's chemical symbol is 'Pb'). A 'plumbarius' was a worker in lead, and as the craft passed through Old French 'plommier' into English, the word followed the metal. The pipes are copper and PVC now, but the name still quietly honors the lead that once carried Rome's water.