You're demonstrating that you don't know what monads are. "Type wrapper function" could mean any number of things (lack of specificity is a bad trait in naming), but it couldn't mean a monad: monads consist of three things, whereas "type wrapper function" implies one thing.

Names don't need to be metaphorical. The purpose of a name is not to teach you what the thing is. For that, you should have a proper explanation from someone who knows. Names have a different, very important purpose: uniquely specifying the thing being named. "Monad" does that very effectively.