'Royal' in the Bible

Now when Athaliah the mother of Ahaziah saw that her son was dead, she arose and destroyed all the seed royal.

But it came to pass in the seventh month, that Ishmael the son of Nethaniah, the son of Elishama, of the seed royal, came, and ten men with him, and smote Gedaliah, so that he died, and the Jews and the Chaldeans that were with him at Mizpah.