EXORD'IUM, noun plural exordiums. [Latin from exodior; ex and ordior, to begin. See Order.] In oratory, the beginning; the introductory part of a discourse, which prepares the audience for the main subject; the preface or proemial part of a composition. The exordium may be formal and deliberate, or abrupt and vehement, according to the nature of the subject and occasion.