arbitration:the official process of settling an argument or a disagreement by sb who is not involved: Both sides in the dispute have agreed to go to arbitration. 強調仲裁糾紛,對糾紛的仲裁用arbitration
sanction:(formal) official permission or approval for an action or a change: These changes will require the sanction of the court. 強調批準,對行為的批準用sanction,該行為特點不是糾紛而是申請批準,仲裁的重點是行為可不可以執行而不是有沒有糾紛。
當然根據實際情況,兩個單詞也可以重合使用,只要語境合適