万一

• Pinyin: wàn yī
• Hanzi breakdown: 万 = 艹 (grass radical, simplified form); 一 = single horizontal stroke (one)

Meaning

Just in case; in the unlikely event that; what if. Used to express a contingency or low-probability scenario that one should still prepare for.

万一 introduces a hypothetical worst case or unlikely scenario (literally 'one in ten thousand'). It is used to urge caution or preparedness. Often appears at the start of a subordinate clause. Similar to 'just in case' or 'in case' in English.

Examples

1. 出门带把伞吧，万一下雨呢？ Take an umbrella when you go out — just in case it rains.
2. 万一你找不到地方，就给我打电话。 In case you can't find the place, just give me a call.
3. 我们应该做好备份，万一系统出问题了怎么办？ We should make a backup just in case the system has a problem.

Usage Guide

Context: everyday, planning, caution

Tone: cautious

Do Say

• 万一明天天气不好，我们就改期举行。(In case the weather is bad tomorrow, we'll reschedule.)
• 多带点钱，万一有急事用得上。(Take extra money just in case you need it in an emergency.)

Don't Say

• 不要用'万一'表示高概率的情况 — '万一'专门用于描述低概率但需要防备的情形 (Don't use 万一 for likely scenarios — it specifically implies a low-probability but worth-preparing-for situation)

Origin & History

万 (ten thousand) + 一 (one) — literally 'one in ten thousand', implying an extremely unlikely but possible scenario.

Cultural Context

Generation: All ages

Social background: Universal