The Oxford English Dictionary says it is "a name given to the bass instrument of the Saxhorn family, usually tuned in B flat or C."

The Chambers Dictionary says it is "a member of the Saxhorn family; the bass tuba."

Percy Scholes describes it as a type of "British Tuba," modelled upon "Wagner's one true tuba - the contra-bass tuba in C." The euphonium is that type of British Tuba he explains that has a fundamental key of B flat; it is known also as the "Tenor Tuba."

So - is it really "a tenor tuba in B flat" as many seem to think or something else? And is it confined to Anglo-Saxon countries or has it already got out?

Ah yes, sorry; we see it has been done in extenso already.