一旦 yīdàn HSK5 once Definitions Defs Origin Strokes Stroke Words Sentences Sents Showing: short time All meanings 11 yīdàn 11 once 10short time 1 1 sentence for 一旦 (yīdàn — short time) 他多年的心血毁于一旦。 tā duō nián de xīnxuè huǐ yú yīdàn. His years of hard work were ruined in an instant. Source: Dong Chinese Dictionary