magnum opus

US /ˌmæɡ.nəm ˈoʊ.pəs/
UK /ˌmæɡ.nəm ˈoʊ.pəs/
"magnum opus" picture
1.

opus magnum, arcydzieło

a large and important work of art, music, or literature, especially one regarded as the most important work of an artist or writer.

:
His latest novel is considered his magnum opus.
Jego najnowsza powieść jest uważana za jego opus magnum.
The symphony is widely regarded as the composer's magnum opus.
Symfonia jest powszechnie uważana za opus magnum kompozytora.