A more thorough explanation:

ACCIDERE

Accidere is a Latin verb that means to fall down or, by extension, to befall or happen to someone.

• He accidit, he fell down.
• Quid accidit? What happened?
• Si quid accidit, if anything happens.

These examples show how accidere can be used to describe physical falling, as well as events that happen to someone. For instance, "Quid accidit?" means "What happened?" and could be used to ask about a car accident or a sudden illness. "Si quid accidit" means "if anything happens" and could be used to express concern about a risky situation, such as a dangerous hike or a long trip.