From my studies I believe it means the King's right to rule, chosen by god, whoses say is above everyone else in parliament and also the Church. Charles I tried to effectively use it on his parliaments, to his peril. Absolutism is the word.
In Medieval and Ancient time periods, kings and emperors were said to be chosen by god, and the rulers themselves often encouraged it to frighten their enemies, and we sometimes carry it on today as tradition.