/ ˈmɑːstəpiːs; NAmE ˈmæstərp-/ (also mas·ter·work ) noun
a work of art such as a painting, film / movie, book, etc. that is an excellent, or the best, example of the artist's work :
The museum houses several of his Cubist masterpieces.
Her work is a masterpiece of (= an excellent example of) simplicity.