Glossary of Literary Theory by Greig E. Henderson and Christopher Brown

Polyphonic novel:

A term used by Mikhail Bakhtin to describe a dialogical text which, unlike a monological text, does not depend on the centrality of a single authoritative voice. Such a text incorporates a rich plurality and multiplicity of voices, styles, and points of view. It comprises, in Bakhtin's phrase, "a plurality of independent and unmerged voices and consciousnesses, a genuine polyphony of fully valid voices." (See also Dialogism.)