Your question is a terminology question that can only be answered within a context.
Essentially both modifiers can be used to identify the character with whom you want your largest audience to identify. This character can be the protagonist or the antagonist -- the character with the broadest 'character arc' in your story.
The trick is to pick one modifier and use it throughout your work.
Another Answer
You may have several main characters, but only one central character. Or you can have one main character and several minor characters. This is an example of context.
A protagonist is the single character whom a given story is about. The protagonist is, therefore, not just a main character, but the main character. Whereas the term main character could refer to any character to whom the author has devoted some significant amount of wordage. Some novels have thirty main characters.
Assuming that you mean the main character of any story, it would be the Protagonist.
Paulie 1998
The protagonist is the main character of the story. He or she may be good, bad, or a combination of both. In any case, s/he is the character at the story's heart and is typically (though not always) the character who changes the most from the beginning to the end of the story or novel.The antagonist is any character in conflict with the protagonist. He or she may be a villain, but may also be a good, kind, loving, caring individual. It is not the character's goodness or lack of it that defines the antagonist: it is his or her relationship to and interaction with the protagonist.Most stories have only one protagonist, but may have many antagonists. In stories where the protagonist is facing an internal conflict or struggle, he or she is also an antagonist.According to what I learned in English class...The protagonist is the main character that can be either good/bad/both. That is the character that you get to know the most.The antagonist is the character that opposes the main character and usually starts the conflict.The protagonist is the main character who is the good guy, and the antagonist is the force against them- it can be another person or even weather, and object, or an animal.
In most games, any of the main character (playable) character can be stoned or petrified.
Metalocolypse, although I don't think he's the MAIN character, he's one of 5-ish.
A chief character is the main character in any story. This is the person that a story will revolve around. For example Sylvester Stallone was the chief character in the Rambo movies.
There r many, I'd say general James longstreet was the main 1, but any general mentioned in that book who has a chapter on its point of view can be considered as a main character
There is Chad from Bleach.
Sackboy is the main character. You can customize him or her in any way you want! Put sticers on him, make him wear a cake outfit and many more from the playstation store.
Characters are any beings in your story, not just the main one. You can have human characters, or animals, or aliens, or even sometimes inanimate objects!
Any way you want to! You're the writer, you have to pick whichever way you want your character to die.