van·guard 
/ˈvænˌgɑɚd/ noun
plural van·guards /ˈvænˌgɑɚd/ noun 1 [count] : the group of people who are the leaders of an action or movement in society, politics, art, etc. — usually singular ▪ a member of the feminist vanguard ▪ They are at the vanguard of a revolution in medical research. [=they are leading a revolution in medical research] ▪ She was in the vanguard of the feminist movement in the early seventies. 2 the vanguard : the soldiers, ships, etc., that are at the front of a fighting force that is moving forward
