van·guard /ˈvænˌgɑɚd/ noun plural van·guards
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