What is the meaning of Magnum_opus?

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

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

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

magnum opus (masterpiece)

magnum opus (greatest work of an author or artist)

magnum opus (process of working with the prima materia to create the philosopher's stone)

magnum opus (great(est) work)

Source: wiktionary.org