Valve gear is particularly full of transatlantic differences, as well as valves vs tubes in many cases the same specific valves can have different names depending on the side of the Atlantic you're on such as EL84 vs 6BQ5. Your high voltage line is called HT in British but B+ in American, while what we'd call an anode in the UK is more commonly called a plate in the US. I'm not sure if it's as fixed but I've usually heard Americans calling what I'd call the heater the filament as well.

While 'valve' makes more sense from the point of view of what it does, 'tube' makes more sense from the point of view of what it is I think.