the great men of a king's court: the nobles and high officials who stand closest to the throne and act together with the king
The word is built from the Aramaic word for "great" (רַב), and it means something like "the great ones." It is not the name of a job. A satrap (אֲחַשְׁדַּרְפַּן) governs a named province and a prefect (סְגַן) holds a named rung on the official ladder, but this word simply gathers up the whole top layer of the court: the men who matter around the king.
All eight uses are in the Aramaic chapters of Daniel, and every one of them is plural and tied to a particular king by a word like "my," "his," or "your." These are never nobles in general; they are always somebody's nobles, and their standing comes from the man they attend. What they do shows the same thing:
- they drink at the king's banquet, and out of the temple cups he has plundered
- they are struck with alarm at the very moment the king is
- they are the ones who seek out Nebuchadnezzar and settle him back on his throne
- their own seals go onto the stone over the lions' den, next to the king's
Daniel puts that closeness to work. Because the nobles share the king's table, they also share his guilt: when Daniel indicts Belshazzar for drinking from the vessels taken out of the temple, he names the nobles in the same sentence. And when Darius wants a sentence to be past recall, it is their signets alongside his that make it stick. Royal power in these stories is never one man acting alone, which is part of why the miracle lands the way it does.