Jehoram, Joram

Facts:

Jehoram was the name of two different kings in the Old Testament. Both these kings were also known as "Joram."

One King Jehoram ruled over the kingdom of Judah for eight years. He was the son of King Jehoshaphat. This is the king that is most commonly known as Jehoram.
The other King Jehoram ruled over the kingdom of Israel for twelve years. He was the son of King Ahab.
King Jehoram of Judah reigned during the time that the prophets Jeremiah, Daniel, Obadiah, and Ezekiel were prophesying in the kingdom of Judah.
Jehoram also reigned during some of the time that his father King Jehoshaphat was reigning over Judah.
Some translations may choose to consistently use the name "Jehoram" when this king of Israel is mentioned and the name "Joram" for the king of Judah.
Another way to clearly identify each one would be to include the name of his father.

(Translation suggestions: How to Translate Names)