1350-1400;Middle English < Middle French < Medieval Latinprēfātia, for Latinpraefātiō a saying beforehand, equivalent to praefāt(us) (past participle of praefārī to say beforehand; see pre-, fate) + -iōn--ion
late 14c., from O.Fr. preface (14c.), from M.L. prefatia, from L. præfatio "fore-speaking, introduction, prologue," from præfatus, pp. of præfari "to say beforehand," from præ- "before" + fari "speak" (see fame). The verb is 1616, from the noun.