Full Idea
We may define a physical event as any change of distribution of energy in any of its forms.
Gist of Idea
A physical event is any change of distribution of energy
Source
Brian Ellis (The Metaphysics of Scientific Realism [2009], 2)
Book Reference
Ellis,Brian: 'The Metaphysics of Scientific Realism' [Acument 2009], p.39
A Reaction
This seems to result in an awful lot of events. My own (new this morning) definition is: 'An event is a process which can be individuated in time'. Now you just have to work out what a 'process' is, but that's easier than understanding an 'event'.