The Hebrew word Ur (אוּר) is a proper noun for the ancient city of Ur, located in southern Mesopotamia (modern Tell el-Muqayyar, Iraq). The name may be related to the Hebrew root meaning "light" or "fire." Ur was the homeland from which God called Abram, launching the redemptive storyline that runs through the entire Bible.
Ur of the Chaldeans was one of the great cities of the ancient world — a wealthy Sumerian city-state with a massive ziggurat dedicated to the moon god Nanna. God's call of Abram out of Ur was a radical act: separation from the world's sophistication and idolatry for a journey of faith. Stephen in Acts 7 highlights Ur as the place "before Abraham lived in Harran" where the God of glory first appeared. The call from Ur establishes the pattern of salvation: God initiates, calls out of darkness into light, and His chosen go by faith into the unknown.