What is the definition of a mass shooting?

https://www.fbi.gov/about/partnerships/office-of-partner-engagement/active-shooter-resources
https://abcnews.go.com/US/deadly-mass-shootings-month-2019/story?id=63449799
Some definitions require a certain amount of people to be shot in a single event, while others require a certain amount of death during a single event. I have included the FBI's definition of active shooter since they are related. I don't believe the FBI has a mass shooting definition.