Chaldea, Chaldean, Chaldeans, Chaldeans', educated men

Facts:

Chaldea was a region in the southern part of Mesopotamia or Babylonia. The people who lived in this region were called Chaldeans.

The city of Ur, where Abraham was from, was located in Chaldea. It is often referred to as "Ur of the Chaldeans."
King Nebuchadnezzar was one of several Chaldeans who became kings over Babylonia.
After many years, around 600 BC, the term "Chaldean" came to mean "Babylonian."
In the book of Daniel, the term "Chaldean" also refers to a special class of men who were highly educated and studied the stars.