Wikipedia
Adonizedek ( Ăḏōnî-ṣeḏeq, "My Lord is right") or Adoni-Zedek was, according to the Book of Joshua, king of Jerusalem at the time of the Israelite invasion of Canaan . His name means "my lord is righteousness" (or "my lord is Zedeq") in Hebrew.
Adonizedek led a coalition of five of the neighboring Amorite rulers ( Hoham, king of Hebron; Piram, king of Jarmuth; Japhia, king of Lachish; and Debir, king of Eglon) in resisting the invasion, but the allies were defeated at Gibeon, and suffered at Beth-horon, not only from their pursuers, but also from a great hail storm. The five allied kings took refuge in a cave at Makkedah and were imprisoned there until after the battle, when Joshua commanded that they be brought before him; whereupon they were brought out, humiliated, and put to death.
According to the Midrash, the name Adoni-zedek is translated as "Master of Zedek" — that is, "of Jerusalem," the city of righteousness ( Genesis Rabbah xliii. 6).