What does arbitrator mean?
The definition of arbitrator
Ar”bi*tra`tor, n.
Etym: [L., fr. arbitrari: cf. F. arbitrateur.]

1 A person, or one of two or more persons, chosen by parties who have a controversy, to determine their differences. See Arbitration.
2 One who has the power of deciding or prescribing without control; a ruler; a governor. Though Heaven be shut, And Heaven’s high Arbitrators sit secure. Milton. Masters of their own terms and arbitrators of a peace. Addison.

Synonyms
— Judge; umpire; referee; arbiter. See Judge.