I'm wondering if the following statement is true: The word "ought" means whatever we ought to believe that it means.

Now, certainly, that statement could be false. There could be a society whose code of ethics states that you must disagree with the code of ethics. But I'm asking whether or not it is false, for us actual humans. And it might be false if you take "we" to mean someone like Adolf Hitler: perhaps Hitler professed his actual beliefs about ethics, and people nowadays think Hitler was so horrible that if Hitler believed something was right, it was probably wrong, and vice versa; and so it would have been best for Hitler's ethical beliefs to be as wrong as possible, so that people who think Hitler was wrong most of the time will come to the correct conclusions. But by "we", I don't mean "each individual human being who has ever lived and ever will live"; I just mean "human society as a whole".

In theory, if this statement were true, we would be able to take sentences like "we ought to believe that murder is wrong" and use them to conclude sentences like "murder is wrong". In practice, this seems like it would only be rarely useful, because it's hard to determine whether or not we ought to believe that a conduct is wrong unless we already know whether or not it is wrong.