A website is a presence on the World Wide Web. As of 2017, there are more than one billion. To qualify as a bona fide site, it must be available over the Internet around the clock.
Tube means a hollow cylinder. An example of a tube is manicotti pasta. The definition of a tube is a pliable container with a screw cap at one end to keep it closed. An example of tube is the container that toothpaste comes in.
Pipe(noun) any long tube or hollow body of wood, metal, earthenware, or the like: especially, one used as a conductor of water, steam, gas, etc. Pipe(noun) a small bowl with a hollow steam, -- used in smoking tobacco, and, sometimes, other substances.