Webster’s Revised Unabridged Dictionary · 1913
Tetrarch
Te′trarch (tē′trärk; 277), n. [L. tetrarches, Gr. τετράρχης, τέτραρχος; τέτρα- (see Tetra-) + ἀρχός a ruler, ἄρχειν to lead; rule: cf. F. tétrarque. See Arch, a.] (Rom. Antiq.) A Roman governor of the fourth part of a province; hence, any subordinate or dependent prince; also, a petty king or sovereign.
Te′trarch, a. Four. [Obs.] Fuller.