Antonym of MONOLOGUE

Monologue : a long speech by one actor in a play or film, or as part of a theatrical or broadcast programme.
Dialogue : a conversation between two or more people as a feature of a book, play, or film.
Prologue : a separate introductory section of a literary, dramatic, or musical work.
Epilogue : a section or speech at the end of a book or play that serves as a comment on or a conclusion to what has happened.
Catalogue : a complete list of items, typically one in alphabetical or other systematic order.

Antonym of Monologue is Dialogue