mediator       
noun [ C ] uk/ˈmiː.di.eɪ.tər/ us/ˈmiː.di.eɪ.t̬ɚ/
 调解员,中间人
a person whose job is to mediate in a disagreement (= talk to the people or groups involved to help them find a solution)
  The governor appointed a mediator and asked both sides to return to the bargaining table. 州长任命了一名调解员,并要求双方回到谈判桌上。 
 Trained mediators are extremely effective and have reduced bullying dramatically. 训练有素的调解员非常有效,并且大大减少了欺凌行为。 
 See: mediate
 - More examples
 - We do not consider him a neutral mediator at all.
 - He could succeed where European mediators have failed because the guerrillas respect him.
 - We will train people in firms who want to become mediators, or send in mediators to help.