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.
Tuber refers to a type of plant structure that has enlarged to store extra nutrients. Many plants use tubers to survive drought or the winter months.