arbitrator:
(also ‘arbiter‘; plural: ‘arbitrators‘)

Arbitrator John C. Fleming, Hays & Owens, Attorneys, Texas
a person, usually an expert in social and legal matters, chosen by the two sides of an argument or dispute to examine the facts and make a right decision to settle the argument or dispute; a judge;
an adjudicator; a referee;
a person who has the ability and power to make an unquestionable decision,

an arbitrator listening to both the parties involved in a dispute
e.g.
In some high level contracts parties involved include arbitration clauses and nominate an arbitrator in advance.
Most people prefer an independent expert arbitrator to an appointed one.
For an informative article on the difference between an arbitrator and a mediator, please visit:
“Answers.com/WikiAnswers”
and
“Difference Between.net”
and
“Bagabuyo & Company — Law Corporation“.
“Answers.com/WikiAnswers”
and
“Difference Between.net”
and
“Bagabuyo & Company — Law Corporation“.
Compare: mediator.
