一旦
yídàn
once (if ever); as soon as
Every meaning
yīdàn
- in one day; in a single moment
- once; as soon as; if ever
Its characters
Words with 一
Words with 旦
Meanings are from Mandarin The Wild’s own dictionary. Levels follow the official HSK word list (the exam’s 2025 syllabus, levels 7–9 shown together).