If I were to name a few Superheroes or Villains, I could end up with a really interesting mixture:
Superman, Batman, The Flash, The Joker, Bane, Cpt. Cold, Vibe, Wonder Woman, Spider Man, Green Arrow, Deadpool, Firestorm, Black Widow, Cpt. America, Iron Man, Ant-Man, Nightwing, Domino, Green Goblin, Sandman... and so many others.
The thing is, while Superman (who isn't anything special if compared to his kin), Flash or Captain America are supernatural — as in, they have abilities beyond human capability (superspeed and durability as examples) — others, simply put, have weapons.
Captain Cold, Iron Man, Green Goblin, The Joker, Batman and Green Arrow have no special powers, other than advanced technology, extreme training and being good strategists. While both training and strategy is what makes them special, anyone can do the same and obtain similar results. In fact, if you simply go back in time to the middle ages, and carry a grenade launcher and a machine gun, you would be a superhero in that time period, just the same as Iron Man is for 2016.
I could picture this
Interviewer: What's your superpower?
Donald Trump: Money
Hence this question: is there any in-universe and out-universe explanations why 'guys with good gear' are considered Superheroes / Supervillains?