Regent
(noun)
A person appointed to administer a country because the monarch is a minor, is absent or is incapacitated.
Origin:
From latin regens, present participle of regere "to rule", from rex "king".
Examples:
- The Duke acted as regent while the King was away.
- The regent was appointed to take care of the kingdom's affairs.
- The young prince will have a regent until he comes of age.
- The regent's rule was marked by peace and prosperity.
- The regent was removed from power after the King's recovery.