The term PLUMBING PIPE can be broken down into three words: PLUMBING, PIPE, and ELL (3 letters). Plumbing is the system of pipes, valves, fittings, and fixtures installed in a building for the distribution of water for drinking, heating, and washing, and the removal of waterborne wastes. A PIPE is a tube or hollow cylinder used to convey fluids, such as water, gas, steam, or other liquid substances. An ELL is a type of plumbing fitting that is used to connect two straight pipes at an angle of 90 degrees. Therefore, the term PLUMBING PIPE can be used to refer to a PIPE used in a plumbing system, specifically one that is connected at an angle of 90 degrees.