in case

From Middle English [Term?]. (This etymology is missing or incomplete. Please add to it, or discuss it at the Etymology scriptorium.)

To allow for the possibility that.
I'll take an umbrella, in case it rains.

I’ve bought a chicken in case grandpa should stay to dine.

Many's the day I've spent by the phone in case you called.
(chiefly Canada, US) If.
In case you need me, I'll be home all day.
- 1861, E. J. Guerin, Mountain Charley, page 17:
  Whenever tempted to resume my sex, I was invariably met with the thought — what then? […] The chances were but few in case I resumed my other character, that I would be able to command the amount necessary for their [her children's] support.

Because event X might occur

Arabic: فِي حَال (fī ḥāl)
Belarusian: у вы́падку (u výpadku), у ра́зе (u rázje)
Bulgarian: в слу́чай (v slúčaj)
Catalan: en cas que (ca)
Chinese:
Mandarin: 如果 (zh) (rúguǒ), 以防 (zh) (yǐfáng)
Cornish: les
Czech: v případě
Danish: i fald, for det fald, at, såfremt, i tilfælde af
French: au cas où (fr)
Georgian: იმ შემთხვევაში, თუ (im šemtxvevaši, tu)
German: falls (de), im Falle
Greek: σε περίπτωση που (se períptosi pou)
Hanunoo: abi
Hungarian: arra az esetre, ha (for the case, if...)
Ido: kaze ke (io)
Italian: qualora (it)
Japanese: …の場合に (…のばあいに, ... no baai ni)
Korean: …은/ㄴ 경우 에 는 (…-eun/-n gyeong'u-e-neun)
Macedonian: во случај (vo slučaj)
Maori: me kore, kei tūpono
Norwegian:
Bokmål: i tilfelle

Nynorsk: i tilfelle
Pannonian Rusyn: у случаю (u slučaju)
Polish: w razie (pl), na wypadek, w przypadku
Portuguese: caso (+ subjunctive), no caso de (+ infinitive), para caso (+ subjunctive)
Russian: в слу́чае (ru) (v slúčaje), на слу́чай (na slúčaj)
Slovak: v prípade
Spanish: por si acaso (es), por si
Swedish: i händelse, ifall (sv)
Telugu: ఒకవేళ (te) (okavēḷa)
Turkish: eğer (tr)
Ukrainian: у ра́зі (u rázi), у ви́падку (u výpadku)
Vietnamese: để chắc chắn
Walloon: si e cas (wa) (+ conditional tense), po si e cas (wa) (+ conditional tense)
Welsh: rhag ofn
Yiddish: טאָמער (tomer)

English