Ur of the Chaldees אור כשדים
Avraham's native city in Mesopotamia, and by tradition the place where he was thrown into a furnace for refusing idols.
Ur is the city from which Jewish history departs. The Torah names it as the birthplace of Terach and his sons and reports flatly that Haran died there in his father's lifetime. Midrash fills in the scene: Avraham smashes the idols in his father's shop, refuses to bow to the fire worshipped by Nimrod, and is thrown into a furnace — from which he emerges unharmed, while the wavering Haran does not.
The city's name means «fire» in Aramaic, and the sages play on the coincidence. The historical Ur was a great Sumerian city on the Euphrates with a ziggurat to the moon god; some commentators place Ur Kasdim further north, near Charan.
After Haran's death Terach leads the family out of Ur toward Canaan — and stops halfway. The road a father abandoned will be finished by his son.