For as expansive and welcoming Terraria is, the game doesn't explain class system very well. In fact, it's hardly mentioned at all, its existence may even be news to you. If you're in that camp, or ...
Classes in Terraria refer to the informal synergy between your Armor and Weapon type, and are generally grouped into Melee, Ranged, Magic, or Summoner builds. This wiki page gives a general overview ...