Let’s not debate semantics.Generically, the term ’audio filter’ can be applied to mean anything which changes the timbre or harmonic content of an audio signal.
Uh, what you just did is precisely to debate semantics. Just so you know.
So your idea of not debating semantics is to say "changes the timbre or harmonic content" can mean adds or subtracts. After all either one is a change. Therefore a filter can also add. Even though we know filters are used to sift through and remove.
No wonder you don't want to debate.