From Longman Dictionary of Contemporary Englishmasterworkmas‧ter‧work /ˈmɑːstəwɜːk $ ˈmæstərwɜːrk/ noun [countable] Aa painting, sculpture, piece of music etc that is the best that someone has done SYN masterpiece ‘Otello’ is Verdi’s riveting masterwork.
Examples from the Corpus
masterwork• Not every track, of course, is a masterwork.• Her face was large and all-but-honest; her voice was a masterwork of treachery.• Now she fears that her latest film, her masterwork, may threaten her ability to work there in the future.• The Book of Ultimate Truths was his masterwork.• Through his glass James Flemyng observed a fine exhibition of model workmen sawing and hammering industriously at his great new masterwork.• He is at home playing anything from symphonic masterworks to swing.• According to the day's briefing notes the masterwork was to be Men of Harlem something to do with his globetrotting, presumably. 