prefix
three ... ago; two ... before last
Prefix used in temporal expressions to mean 'three units ago' or 'the one before the one before last'. Most commonly seen in 一昨昨日 (いっさくさくじつ, 'three days ago') and 一昨昨年 (いっさくさくねん, 'three years ago'). Not freely productive; limited to a few fixed compounds.
See also: 一昨昨日
一昨昨日の出来事をまだ覚えている。
I still remember what happened three days ago.
一昨昨年の統計を見ると、傾向がわかる。
Looking at the statistics from three years ago, you can see the trend.
The full word meaning 'three days ago', formed with this prefix.
The full word meaning 'three years ago', formed with this prefix.
Means 'the day before yesterday' (two days ago), using a different reading for the same kanji 一昨.
Compound of 一昨 (いっさく, 'one before last') reduplicated to indicate an additional step back in time. The exact historical derivation is uncertain, but the pattern is analogous to other temporal prefixes.