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.
Barometer. An apparatus for measuring the pressure exerted by the atmosphere. It consists, in the mercurial form, of a glass tube, over 31 inches long, closed at one end, filled with mercury and inverted, with its open end immersed in a cistern of mercury.