一昨晩(いっさくばん) いっさくばん noun the night before last formalwrittentime-general 1. the night before last The evening or night of the day before yesterday. A formal, largely written word; in speech people usually say おとといの晩(ばん) or おとといの夜(よる). 一昨晩(いっさくばん)、雨(あめ)が降(ふ)った。🔊 It rained the night before last. 一昨晩(いっさくばん)から熱(ねつ)が続(つづ)いている。🔊 I've had a fever since the night before last. 一昨晩(いっさくばん)の会議(かいぎ)で決(き)まったことを、今朝(けさ)全員(ぜんいん)にメールで知(し)らせた。🔊 This morning I emailed everyone about what was decided at the meeting the night before last. RegisterFormal and mostly written — news reports, police statements, and business correspondence. In conversation おとといの晩(ばん) is the natural choice.Related words昨晩(さくばん): last night今晩(こんばん): tonight一昨日(おととい): the day before yesterday一昨年(おととし): the year before lastThe prefix 一昨(いっさく) means "one before last" and appears in a small closed set of time words. Related Words Related: 昨晩(さくばん) Related: 一昨日(おととい) Related: 今晩(こんばん) (tonight) general Added 2026.8.4 15:26 · Revised 2026.10.4 9:59 30000/30391_issakuban