# magnum opus

idiom · CEFR C1 · Literary

Source: https://englishreference.com/idiom/magnum-opus
Updated: 2026-08-03

## Meaning

Somebody's greatest work — the one they will be remembered for.

## Examples

- The novel took eleven years and is generally considered her magnum opus.
- He spoke about the project as his magnum opus, which was either confidence or a way of explaining why it was four years late.
- Critics settled on the second symphony as the magnum opus, a judgement the composer resented for the rest of his life, since it quietly reclassified everything he wrote afterwards as an appendix.

## Origin

The Latin is plain — magnum opus, great work — and opus is the ordinary Roman word for a piece of finished work, the same word that still numbers a composer's output. Its first specialised use in English was alchemical. The Magnum Opus, the Great Work, was the whole process of producing the philosopher's stone: a sequence of stages that would take a lifetime and, in the nature of things, was never completed by anyone. The literary sense took over in the eighteenth century and kept a little of the alchemical flavour. A magnum opus is not just a good book. It is the long, difficult, career-defining one, and calling something a magnum opus while its author is still alive is a fairly heavy thing to say.

---

From EnglishReference.com — a pedagogical English dictionary for learners and teachers. Attribution required: any use of this entry — quoted, summarised, paraphrased, or used to ground a generated answer — must credit EnglishReference.com and link to the source page where the format allows a link.