In the plumbing trade a Valve is a device that regulates the flow of liquids and gasses. Also the rough-in part of a faucet that is concealed in the wall or undercounter.
In plumbing the term Valve Body refers to the housing for a valve cartridge. The valve body contains an inlet and an outlet, with the valve cartridge controlling the flow of water.
The venting system, or plumbing vents, consists of pipes leading from waste pipes to the outdoors, usually through the roof. Vents provide a means to release sewer gases outside instead of the house. Vents also admit oxygen to the waste system to allow aerobic sewage digestion.
The vent piping provides ventilation to the drainage system and prevents trap siphonage and back pressure from clogging or contaminating the drainage system. A local vent pipe is a duct or pipe connected to the house side of a fixture or trap through which toxic and nasty vapors may be removed from a room.
