Arbitrator

1. n. One who has the power of deciding or prescribing without control; a ruler; a governor.
2. n. A person, or one of two or more persons, chosen by parties who have a controversy, to determine their differences. See Arbitration.

The word meanings were obtained from OPTED(The Online Plain Text English Dictionary), which is based on “The Project Gutenberg Etext of Webster’s Unabridged Dictionary” which is in turn based on the 1913 US Webster’s Unabridged Dictionary (See Project Gutenburg), as a text file.