一旦(いったん) いったん adverb once, for a moment, temporarily descriptive See also: 一端(いったん) (one end, a part (一端)) 1. once, when once Used to indicate that once something happens, a consequence follows. 一旦(いったん)決(き)めたら最後(さいご)までやる。🔊 Once I've decided, I see it through to the end. 一旦(いったん)火(ひ)がつくと、なかなか消(き)えない。🔊 Once it catches fire, it's hard to put out. 一旦(いったん)約束(やくそく)したことは守(まも)るべきだ。🔊 You should keep a promise once you've made it. 2. for the time being, temporarily For a short period before continuing or changing. 一旦(いったん)休憩(きゅうけい)しましょう。🔊 Let's take a break for now. 一旦(いったん)帰(かえ)ってから出直(でなお)します。🔊 I'll go home first and then come back. Usage: 一旦(いったん) has two main uses:1. CONDITIONAL (once...): Often followed by と or ば一旦(いったん)〜と/ば (once ~ happens)Emphasizes that something triggers an irreversible or significant change2. TEMPORARY (for now): Indicates a pause before continuing一旦(いったん)止(と)める (to stop temporarily)一旦(いったん)保留(ほりゅう)にする (to put on hold for now)Common patterns一旦(いったん)〜したら (once you do ~)一旦(いったん)家(いえ)に帰(かえ)る (to go home first)一旦(いったん)落(お)ち着(つ)く (to calm down for a moment) general Added 2026.1.13 21:42 · Revised 2026.9.2 13:01 04000/04099_ittan