Definition of a Thriller

Wikipedia defines a thriller as:

"a broad genre of literature, film and television that includes numerous and often overlapping sub-genres"

It also lists the sub genres, which are given as: Action thriller, Conspiracy thriller, Crime thriller, Disaster thriller, Drama thriller, Eco-thriller, Erotic thriller, Legal thriller, Medical thriller, Political thriller, Psychological thriller, Spy thriller (also a sub genre of spy fiction), Techno-thriller and Religious thriller.