Concise Bible Dictionary:
These are mentioned repeatedly in Daniel along with magicians, astrologers, and soothsayers. These Chaldeans were a particular class of learned men, forming with others the Magi, or wise men of Babylon. In Daniel 5:11 it is said that Daniel had been made “master” of them, doubtless because it had been discovered that he had more wisdom than all of them. When the Chaldeans, were called in before the king to interpret the writing on the wall, Daniel was not among them, and we may be sure he kept himself aloof from such. See MAGI.