arbiter       
noun [ C ] uk/ˈɑː.bɪ.tər/ us/ˈɑːr.bə.t̬ɚ/
 仲裁人,公断人,裁决人;权威人士
someone who makes a judgment, solves an argument, or decides what will be done
  the arbiters of fashion/taste 时尚/鉴赏权威 
 The government will be the final arbiter in the dispute. 政府将对争端作出最终裁决。