—n. 1. a preliminary discourse; a preface or introductory part of a discourse, poem, or novel.
2. an introductory speech, often in verse, calling attention to the theme of a play.
3. the actor or actress who delivers this.
4. an introductory scene, preceding the first act of a play, opera, etc.
5. any introductory proceeding, event, etc.: Appetizing delicacies were the prologue to a long dinner.
—v.t. to introduce with or as if with a prologue. Also,pro'log.