What does 2 Chronicles 21:2 mean?

Jehoram had several brothers—Azariah, Jehiel, Zechariah, Azaryahu, Michael, and Shephatiah. They were all sons of Jehoshaphat, king of Israel. 2 Chronicles 21:2 - Modern Text Bible

(Jehoram wasn't an only child; he had many brothers, all sons of Jehoshaphat. The mention of 'king of Israel' here refers to the southern kingdom, Judah.)