“Magnum Opus: A great work of art or literature, especially a writer’s culminating and greatest achievement; masterpiece. Plural: magna opera, magnum opuses,
‘It was the magnum opus of a fat spoiled rich boy who could write like an angel about landscape and like an adolescent about people.’ Norman Mailer, Cannibals and Christians”
Excerpted from: Grambs, David. The Random House Dictionary for Writers and Readers. New York: Random House, 1990.