noun

1. A great or important work of literature, music or art, a masterpiece.

2. The best, most popular, or most renowned achievement of an author or artist, representing their major life effort.

   “The 1949 novel Nineteen Eighty-Four is widely considered to be George Orwell's magnum opus.”

3. The process of working with the prima materia to create the philosopher's stone.

Synonyms: masterpiece, opus magnum