van·guard / ˈvanˌgärd/ • n. a group of people leading the way in new developments or ideas: the experimental spirit of the modernist vanguard. ∎  a position at the forefront of new developments or ideas: the prototype was in the vanguard of technical development. ∎  the foremost part of an advancing army or naval force.DERIVATIVES: van·guard·ism / -ˌizəm/ n.van·guard·ist n.

vanguard foremost division of an army. XV. Earlier vandgard, var. of †vantgard, aphetic of †avantgard (XV) — (O)F. avant-garde, †avan-garde, f. avant before + garde GUARD.