plumbing

from The American Heritage® Dictionary of the English Language, 5th Edition.

• noun The pipes, fixtures, and other apparatus of a water, gas, or sewage system in a building.
• noun The work or trade of a plumber.
• noun Informal An arrangement of bodily vessels or ducts.

from The Century Dictionary.

• noun The art of casting and working in lead (also, by extension, in other metals put to similar uses), and applying it to various purposes connected with buildings, as in roofs, windows, pipes, etc.
• noun The act or process of ascertaining the depth of anything.
• noun Lead pipes and other apparatus used for conveying water or other liquids through a building.

from the GNU version of the Collaborative International Dictionary of English.

• noun The art of casting and working in lead, and applying it to building purposes; especially, the business of furnishing, fitting, and repairing pipes for conducting water, sewage, etc.
• noun The lead or iron pipes, and other apparatus, used in conveying water, sewage, etc., in a building.

from Wiktionary, Creative Commons Attribution/Share-Alike License.

• noun uncountable The pipes, together with the joints, tanks, stopcocks, taps and other fixtures of a water, gas or sewage system in a house or other building.
• noun uncountable The trade or occupation of a plumber.
• noun uncountable, informal A system of vessels or ducts in the human body, especially the genitourinary system.
• noun countable A Murasugi sum where each disk summed along has its boundary subdivided into four segments.

from WordNet 3.0 Copyright 2006 by Princeton University. All rights reserved.

• noun measuring the depths of the oceans
• noun utility consisting of the pipes and fixtures for the distribution of water or gas in a building and for the disposal of sewage
• noun the occupation of a plumber (installing and repairing pipes and fixtures for water or gas or sewage in a building)