一昨夜(いっさくや) いっさくや noun the night before last formaltime-general 1. the night before last The night of two days ago — the evening preceding last night. 一昨夜(いっさくや)は眠(ねむ)れなかった。🔊 I couldn't sleep the night before last. 事件(じけん)は一昨夜(いっさくや)起(お)きた。🔊 The incident happened the night before last. 一昨夜(いっさくや)遅(おそ)くに帰宅(きたく)したので、まだ疲(つか)れが残(のこ)っている。🔊 I got home late the night before last, so I'm still tired. A somewhat formal word, common in writing and news. In casual speech, おとといの夜(よる) is more usual.Similar words昨夜(さくや): last night一昨日(おととい): the day before yesterday一昨夜(いっさくや): the night of the day before yesterday general Added 2026.5.24 11:02 · Revised 2026.9.2 13:02 27500/27989_issakuya