exordium

a short section (as of a book) that leads to or explains the main part in his exordium the author warns his readers that they should expect a radically different interpretation of the causes of the war Synonyms introduction, foreword, intro, preamble, preface, prelude, proem, prologue (also prolog), prolusionRelated Words beginning, commencement, initiation, opening, origin, origination, outset, startNear Antonyms envoi (or envoy), postscript; aftermath; cessation, close, closing, conclusion, end, finale, finish, stop, terminationAntonyms epilogue (also epilog)