Webster’s Revised Unabridged Dictionary · 1913
Arbiter
Ar′bi·ter (är′bĭ·tẽr), n. [L. arbiter; ar- (for ad) + the root of betere to go; hence properly, one who comes up to look on.] 1. A person appointed, or chosen, by parties to determine a controversy between them.
☞ In modern usage, arbitrator is the technical word.
2. Any person who has the power of judging and determining, or ordaining, without control; one whose power of deciding and governing is not limited.
For Jove is arbiter of both to man. Cowper.
Syn. — Arbitrator; umpire; director; referee; controller; ruler; governor.
Ar′bi·ter, v. t. To act as arbiter between. [Obs.]