Is a bassoon a instrument

Answer 1

Yes it is and no it isn't.

While the term tenoroon has been applied to tenor or smaller bassoons it has also been applied, somewhat erroneously, to the bass Oboe and to an organ stop.

Tenoroon is somewhat generic and in a modern context referrs to any of the smaller bassoons. In order to avoid ambiguity and to distinguish the smaller bassoons in F and G from those an octave higher than the regula bassoon, the term tenor bassoon is being applied to a professional model of tenoroon, currently built in F by Wolf.

Answer 2

Yes