noun
A person who intervenes in a dispute to help the parties reach a resolution, often in legal, business, or interpersonal contexts.
彼は労働争議の仲裁者として選ばれた。
He was chosen as the arbitrator for the labor dispute.
仲裁者が両者の話し合いを助けた。
The mediator helped the two parties talk things over.
Compound of 仲裁 (arbitration, mediation) and 者 (person). 仲裁 is from 仲 (relationship) and 裁 (judge).