The definition of risk I agree with the comments so far. Chris's definition defines risk with a broad scope and encompasses more situations and activities than health and safety alone.
It wouldnt fly in my organisation when it comes to engaging with workers and helping them understand risk. Just as it is a broad definition for Chris, it would be too abstract for many of my workers to easily understand. I tend to phrase hazards and risk more as "What are the things in <this job> that can hurt you? How likely is this <thing> to hurt you?"
The definition works at a higher level. You would expect managers and Directors to be taking a more broad view of the subject.