(n.) A beginning; an introduction; especially, the introductory part of a discourse or written composition, which prepares the audience for the main subject; the opening part of an oration.

aggravated assault aggression amphibious attack armed assault assailing assailment assault attack avant-propos banzai attack blitz blitzkrieg boost charge coinage counterattack counteroffensive coup de main crippling attack dead set at descent on discovery diversion diversionary attack drive exordium flank attack foreword front matter frontal attack frontispiece gas attack head-on attack hike increase infiltration innovation introduction invention leap lightning attack lightning war mass attack megadeath mugging neologism new phase novelty offense offensive onset onslaught overkill overture panzer warfare postulate preamble preface prefix prefixture preliminary prelude premise presupposition proem prolegomena prolegomenon prolepsis prologue protasis push run against run at rush sally shock tactics sortie strike unprovoked assault upgrade verse voluntary wax