expression, noun
common knowledge; public knowledge; well-known fact
A formal or written expression for something widely known and accepted as true. Often used in legal, journalistic, or explanatory contexts.
彼が辞任したことは公知の事実だ。
It is common knowledge that he resigned.
その問題は公知の事実として扱われている。
The issue is treated as a well-known fact.
Similar meaning, but 周知の事実 emphasizes that something is widely known among a specific group or the general public, while 公知の事実 has a slightly more official or public-domain nuance.
Compound of 公知 (public knowledge) and 事実 (fact). The exact historical derivation is uncertain, but it follows a common pattern of formal noun phrases in Japanese.