Yes. Zorro is a Superhero. Batman is considered a Superhero, so....ergo....Zorro is as well.
I think overall, we consider these two to be superheroes not b/c of "powers".....but just b/c of the way they're dressed. The two have a real theatricality to them.
Realistically, they're heroes b/c they're just men in masks. But, in the grand scheme of things, they're superheroes I think.
Funny thing is, too, is Robin Hood a superhero? or a hero? B/c, in many ways...Zorro and Robin Hood are alike. Zorro is a freedom fighting rebel of the tyrant state, essentially stealing from the corrupt and giving power to the poor and defenseless. Difference between him and Robin is he's got a cool costume, cool horse.....rich, with a mansion......a loyal servant.....hmm......