expression, godan verb (-ru, irregular)
common; frequent; often the case
Used to describe something that happens often or is a common occurrence. Often appears in the pattern よくあること (a common thing).
この辺りでは、地震はよくあることです。
Earthquakes are a common occurrence around here.
そんなミスはよくあるから、気にしないで。
That kind of mistake happens often, so don't worry about it.