ROGET THESAURUS
prolusion
Precursor
N
precursor, antecedent, precedent, predecessor, forerunner, vancourier, avant-coureur, pioneer, prodrome, prodromos, prodromus, outrider, leader, bellwether, herald, harbinger, foreboding, dawn, avant-courier, avant-garde, bellmare, forelooper, foreloper, stalking-horse, voorlooper, voortrekker, prelude, preamble, preface, prologue, foreword, avant-propos, protasis, proemium,
prolusion, proem, prolepsis, prolegomena, prefix, introduction, heading, frontispiece, groundwork, preparation, overture, exordium, symphony, premises, prefigurement, omen, precursory, prelusive, prelusory, preludious, proemial, introductory, prefatory, prodromous, inaugural, preliminary, precedent, a precedent embalms a principle.