Verismo is a word which refers to a type of literature and a type of opera that was popular towards the end of the 19th century and the beginning of the 20th century. The Italian word "verismo" means "realism". In literature the main verismo writers were the Frenchman Émile Zola, the Norwegian dramatist Henrik Ibsen and the Italian writer Giovanni Verga. The composer Pietro Mascagni used a story by Verga for his opera Cavalleria rusticana. This was a short, one-act opera which became extremely popular. Several composers were inspired by it and wrote similar works. The only one of these which is still regularly performed is Pagliacci by Ruggero Leoncavallo. These two short operas are often performed on the same evening. They are known together as "Cav and Pag".
Verismo operas are generally based on stories about ordinary people from the working classes rather than about kings or gods or aristocrats. There is often a lot of violence in the stories as people love one another with great passions, which often leads to murder. Bizet's opera Carmen is typical of that kind of story, although it was composed before the verismo tradition was really popular.