tetrarch
adjEtymology Borrowed from Latin tetrarchēs, from Ancient Greek τετράρχης (tetrárkhēs), from τετρα- (tetra-, “four”) + -άρχης (-árkhēs, “ruler, leader”).
tetrarch
nounUS /ˈtɛtɹɑɹk/ · UK /ˈtɛtɹɑːk/
Etymology Borrowed from Latin tetrarchēs, from Ancient Greek τετράρχης (tetrárkhēs), from τετρα- (tetra-, “four”) + -άρχης (-árkhēs, “ruler, leader”).
1
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.
2
Each of the four members of a jointly ruling tetrarchy, notably of the Roman Empire since Diocletian.
3
An officer in charge of a fourth part of a phalanx in Ancient Greece.