mas·ter·piece / ˈmastərˌpēs/ • n. a work of outstanding artistry, skill, or workmanship: a great literary masterpiece the car was a masterpiece of space-age technology. ∎  an artist's or craftsman's best piece of work: the painting is arguably Picasso's masterpiece. ∎ hist. a piece of work by a craftsman accepted as qualification for membership of a guild as an acknowledged master.

masterpiece a work of outstanding artistry, skill, or workmanship; originally, a piece of work by a craftsman accepted as qualification for membership of a guild as an acknowledged master.