Chaldean has both a historical and a modern meaning.
Chaldean is a Hellenistic term for the Ancient Babylonians.
The Chaldeans seized the Assyrian capital, Nineveh, in 612 B.C., and destroyed it. They soon conquered all of Mesopotamia and Syria. In 586 B.C. they conquered Judah and scattered the Jewish nation. This began the period of Jewish history known as the exile. Although the Chaldeans only remained in power for fifty years, they were responsible for founding what is known as the Neo-Babylonian empire. Elaborate and beautiful palaces and buildings were constructed by the Chaldeans. The famous Hanging Gardens of Babylon were made during the Chaldean rule.
The Chaldeans’ short reign is chronicled in the Biblical story of Daniel. As a teenager, Daniel was captured by the Chaldean army during its first attack on Jerusalem. While Daniel served under Nebuchadnezzar II, one of only a few Chaldean kings, he interpreted dreams, witnessed the miraculous survival of Shadrach, Meschach and Aben-nego in the fiery furnace, and accurately predicted Nebuchadnezzar’s descent into madness before reclaiming his throne. Under the rule of Nebuchadnezzar’s son, Belshazzar, Daniel witnessed the writing on the wall, which he interpreted for Belshazzar as a sign of Belshazzar’s imminent downfall. The very next day, the Persians invaded, killed Belshazzar, and took over the Babylonian empire.
Chaldeans are an Eastern Rite Catholic minority originating in the Middle East. Most speak a language called "Chaldean", or "Syriac", which is a branch of Aramaic. Chaldeans usually speak the dominant language of their country as well (usually Arabic). They are closely related to modern Assyrians. Many Chaldeans have immigrated to the U.S. from Iraq due to anti-Christian persecution since the 2003 invasion. Since the Coalition Forces invasion of Iraq, it has been very difficult for Chaldeans to immigrate to the U.S. any longer. Those fleeing persecution have been forced to go to Syria and Jordan. Saddam Hussein's former deputy president, Tariq Aziz, was a Chaldean Christian. There are large Chaldean communities in Los Angeles and Detroit.