A governor or ruler of a quarter of a country, especially of a fourth part of a province in or client state of Ancient Rome.

plural of tetrarch

Of or pertaining to a tetrarch or tetrarchy.

plural of tetrarchate

(historical, Roman antiquity) A tetrarchy.

Relating to a tetrarchy.

(politics) A government where power is shared by four people, especially (historical) the Herodian tetrarchy established in Judea after the death of Herod and the Tetrarchy of Diocletian which ruled the Roman Empire in the years 293-313.

plural of tetrarchy