['t?tr?:k]
¦ noun (in the Roman Empire) the governor of one of four divisions of a country or province.
?one of four joint rulers.
?archaic a subordinate ruler.
Derivatives
tetrarchy noun (plural tetrarchies).
Origin
OE, from late L. tetrarcha, from L. tetrarches, from Gk tetrarkhes, from tetra- 'four' + arkhein 'to rule'.