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.
Tube pans are classically made from metal, and they may be treated so that they are non-stick, or left unfinished. Some come in two pieces, with a removable bottom which is designed to facilitate the removal of delicate or tricky baked dishes.