Film genre originally applied to plays with plots with moral issues where good versus evil were the main focus. Later, the films of D. W. Griffith, such as "Way Down East in (1920), the personal and social problems of women are portrayed in particularly melodramatic way, and the emphasis become more on characters themselves. In films like Stella Dallas (1937) or Douglas Sirk's "All That Heaven Allows," the happy ending plot gives way to the female character sacrificing everything to a more noble cause.

Source: Art & Architecture Thesaurus

http://vocab.getty.edu/page/aat/300375153