Au cas où is a commonly used French expression meaning “just in case”. Students often mistakenly pronounce the S in cas (case). This is wrong as the S is silent. Hence, [ka].
Au cas où
just in case
Example sentences
J’ai toujours un sac de couchage dans la voiture au cas où.
I always have a sleeping bag in the car, just in case.
Apporte un parapluie, au cas où.
Bring an umbrella, just in case.
Note that in this sentence, the expression au cas où is followed by the conditional tense.
Prends un blouson au cas où il ferait frais.
Take a jacket just in case it’s cook out.
