obscurity; dustbin of history; long-forgotten memory
Used for things that have been completely forgotten, often with a dramatic or literary tone. Common in phrases like 忘却の彼方に消える or 忘却の彼方へと追いやられる.
The incident faded from people's memories and was consigned to the dustbin of history.
Even the once-popular buzzwords are now long-forgotten.
忘却 is the abstract noun 'oblivion' or 'forgetting'; 忘却の彼方 is the full phrase meaning 'beyond oblivion' or 'into obscurity'.
彼方 alone means 'beyond' or 'the other side'; combined with 忘却 it creates the set expression.
Standard kanji spelling for this expression.
Kana spelling of 彼方; slightly softer or more literary feel.
A set phrase combining 忘却 (oblivion) and 彼方 (beyond, that side). The expression is not ancient but is a natural literary collocation.