arbiter

Etymology

From Middle English arbiter, arbytour, arbitre, from Old French arbitre, from Latin arbiter (“a witness, judge, literally one who goes to see”).

noun

1. A person appointed, or chosen, by parties to determine a controversy between them; an arbitrator.
   In order to protect individual liberty there must be an arbiter between the governing powers and the governed. 1931, William Bennett Munro, The government of the United States, national, state, and local, page 495
2. (with of) A person or object having the power of judging and determining, or ordaining, without control; one whose power of deciding and governing is not limited.
   Television and film, not Vogue and similar magazines, are the arbiters of fashion.
   The dreadnought is the ultimate arbiter of space warfare; millions of tons of metal, ceramic, and polymer dedicated to the projection of firepower against an enemy vessel of like ability. No sane commander would face a dreadnought with anything less than another dreadnought. 2008, BioWare, Mass Effect, Redwood City: Electronic Arts, →OCLC, PC, scene: Starships: Dreadnought Codex entry
3. (electronics) A component in circuitry that allocates scarce resources.

verb

1. (transitive) To act as arbiter.
   Worse, since there was no institution to arbiter disagreements between Parliament and the government, whenever Parliament voted against the government on the smallest issues, coalitions fragmented, and governments had to be recomposed. 2003, Jean-Benoit Nadeau, Julie Barlow, Sixty Million Frenchmen Can't be Wrong: Why We Love France But Not the French, page 116