tripartite       
adjective  formal uk/ˌtraɪˈpɑː.taɪt/ us/ˌtraɪˈpɑːr.tait/
 涉及三方的;包括三部分的
involving three people or organizations, or existing in three parts
  A tripartite agreement brought together government, industry, and trade unions in an effort to reduce unemployment. 一项三方协议使政府、企业和工会联合起来,努力减少失业人口。 
 Compare: bipartite