Protagonist vs hero

[micaelo]

Is there a difference between these two words when referring to the main character in a work of fiction? I can't find any. Thank you.

 

[meez]

Protagonist describes merely the main character who is not necessarily a hero.
A Hero on the other hand can be the protagonist but doesn't have to.

 

[Anglika]

The hero of a novel is the chief character [male] whereas a protagonist can be any character involved in the action.