Risk means more things can happen than will happen  - Elroy Dimson 

I view risk as the dispersion of countable events. Uncertainty is the events that are not countable, yet the Dimson definition hits home as a key description. It is the range of what is possible, both good and bad. For volatility, the dispersion from the mean says more things can happen than will. For uncertainty, more possibilities are riskier than fewer. Although we focus on the bad, risk can also be a positive.