Definition of roman à thèse in English:
roman à thèse
(also roman a thèse)
noun rə(ʊ)ˌmɒ̃ a ˈtɛzrə(ʊ)ˌman a ˈtɛz
A novel that seeks to further a viewpoint or expound a theory.
Origin
Early 20th century; earliest use found in Author. From French roman à thèse from roman + à with + thèse.