‘遇难’ (yù nàn) is a formal, somber verb meaning 'to perish' or 'to die in an accident or disaster.' It literally combines 遇 (yù, 'to encounter') and 难 (nàn, 'calamity' or 'disaster'), so the phrase conveys the idea of 'encountering a calamity' — specifically, one that results in death. It is never used for natural death due to illness or old age; rather, it refers exclusively to sudden, tragic, externally caused fatalities — such as in earthquakes, shipwrecks, plane crashes, or mining accidents.

The term carries strong emotional weight and appears frequently in official reports, news headlines, and memorial contexts. It is typically used with subjects like people, passengers, workers, or soldiers — never animals or objects — and often appears in passive or descriptive constructions (e.g., ‘不幸遇难’, ‘全部遇难’). Because of its gravity, it is avoided in casual speech and never used humorously or lightly.