‘Se7en’ (Seven) refers to the 7 deadly signs or capital vices :
7 = V
US Thriller directed by David Fincher, released on September 22, 1995.
Written by: Andrew Kevin Walker
Produced by: Arnold Kopelson and Phyllis Carlyle
Starring: Brad Pitt, Morgan Freeman, Kevin Spacey, John C. McGinley and Gwyneth Paltrow.