expression, noun
Emphasizes that something happened so long ago it feels distant or irrelevant now. Often used in the pattern とうの昔に〜した (did something ages ago). Similar to とっくの昔 but slightly more formal.
See also: とっくの昔
彼が引っ越したのはとうの昔のことだ。
It was a long time ago that he moved away.
その問題はとうの昔に解決している。
That problem was solved ages ago.
More casual and conversational than とうの昔, but nearly identical in meaning.
The とう is an old adverbial form of 疾し (とし, 'quick, early'), meaning 'already' or 'long since'. Combined with の昔 (のむかし, 'of old times'), it literally means 'the long-ago past'. The exact historical derivation is uncertain, but the expression is well-established in modern Japanese.