And everyone in the UK knows what a tube is. And actually, I guess
"vacuum tube" is just as good a description of them as "valve" ...

Arfa


I don't know what the term tube to the general public in the USA means but
in the UK it means an open ended cylinder. You would not retain much
vacuum in an open ended pipe.

I think I would dispute that the description "open-ended" is in any way
implied in the definition of a tube ...

Arfa