A / arbī^trātor
noun

arbī^trātor

gen. arbī^trātōris · gender masculine · decl. 3rd
id., in late Lat. = arbiter, II. B.
a master; ruler; lord
a master, ruler, lord: JVPPITER ARBITRATOR, Inscr. Gud. 7, 5.—Hence a place in the tenth district at Rome is called Pentapylon Jovis arbitratoris, Publ. Victor. Reg. 10.