Masterwork (noun)

1. A work of art, music, or literature that is considered to be the best or most important work created by a particular artist, composer, or author.
2. A masterpiece, a work of exceptional skill or creativity.

Origin:

The word 'masterwork' was first recorded in english language in the early 17th century, from the dutch word 'meesterwerk', which meant a work by a master artist. the word was later adopted in english with the same meaning.

Examples:

1. The 'Mona Lisa' is considered Leonardo da Vinci's masterwork.
2. Beethoven's Ninth Symphony is considered one of the greatest masterworks of classical music.
3. Shakespeare's 'Hamlet' is considered a masterwork of English literature.
4. Michelangelo's 'David' is considered a masterwork of Renaissance sculpture.
5. Rembrandt's 'Night Watch' is considered a masterwork of Dutch Baroque painting.