triad

1. N-COUNT The Triads were Chinese secret societies in old China that were often associated with organized crime. 三合会; 旧中国的秘密犯罪组织[usu pl, oft N n]

2. N-COUNT A triad is a group of three similar things. 三个一组[正式] [oft N 'of' n]

For the faculty, there exists the triad of responsibilities: teaching, research, and service. 教员要承担三项责任:教学、研究和服务。