A pipe is a hollow tube that liquid flows through. When your kitchen pipes get clogged, call a plumber. A pipe is also something to put tobacco in and smoke. Old pictures of Santa show him smoking a pipe.
Water moves through pipes before it comes flowing out of your faucets. Other substances, like oil and gas, also flow through pipes. These pipes are usually made of metal or a very sturdy kind of plastic. Other kinds of pipes include the ones you make music with and the one your uncle has to smoke outside, because it's so smelly. Pipe comes from the Vulgar Latin pipa, "tube-shaped musical instrument."