expression
emergency; unexpected event; rare possibility
Refers to a hypothetical or unlikely negative event, often used in the context of preparation or insurance. The phrase is a set expression combining もしも (if by any chance) and こと (thing/matter).
もしものことに備えて、保険に入っておいたほうがいい。
You should get insurance in case of an emergency.
もしものことがあったら、この番号に電話してください。
If something unexpected happens, please call this number.
A compound of もしも (if by any chance) + の (possessive particle) + こと (thing/matter). The phrase literally means 'the thing of if by any chance,' and it became a set expression for an unforeseen event.