Lets settle this once and for all cause i say no but i don't understand why the mods allow people to use it in fights
No. It is not animation originating in the eastern world. But it still extremely popular in anime fandom.
Every few months this comes back up. AtLAB isn't anime. It's not even in a gray area. Whenever I've asked someone saying that AtLAB is anime what makes it anime? the response is usually no response. When someone does respond, it usually boils down to that it's good, almost as if not being anime = bad therefore we all must say it's anime or you're saying it sucks. It's either that or really vague stuff like it has an overarching story and there are fights, both of which are zero factors in something being anime.
But it still extremely popular in anime fandom.
While true, this is a complete and total zero factor in whether it's anime or not.
i don't understand why the mods allow people to use it in fights
You might want to check the battle forum rules. Only one of the characters in a battle has to be an anime character. As for the Avatar character vs Avatar character battles, which are allowed because we have Avatar in our wiki, you can obviously just ignore those threads altogether.
The only definition that covers all of undeniable anime imo is animation created in Japan where Japanese people have a noticeable role in the creative process. It being Japanese is the entire point that it's referred to using the Japanese word for animation rather than just "animation" or "cartoons".
Any definition with a criteria that eliminates duh of course this is anime anime is a clear cut flawed one. It'd be like defining a movie in a way that Godfather or Citizen Kane somehow aren't counted as movies.