From the French meaning novel with a key, a novel where the fiction represents actual persons and events thinly disguised by pseudonyms. The reader who has the key can read the novel as real history.
Editors. "Roman a clef". The Literary Encyclopedia. First published 01 November 2001
[http://www.litencyc.com/php/stopics.php?rec=true&UID=966, accessed 30 June 2015.]