* A misspelling: Perhaps you meant "Nile", the famous river in Africa.
* A regional term: It could be a local word or dialect term in a specific place. If you could provide more context, like where you encountered this word, I might be able to help.
* A fictional word: It could be a made-up word from a book, movie, or game.
To help me understand what "neilos" means, please provide more information.