The last definition for this blog is "denial-of-service". According to Wikipedia, "In computer security, a denial-of-service attack (DoS attack) is an attempt to make a computer resource unavailable to its intended users." However, this does not really reflect the conditions that could occur in an industrial facility when affected by a cyber event. For example, loss of a variable speed drive that causes a pump to shut down is a "denial of service"; that is, the pump doesn't work. A more subtle case is when cyber events lead to erroneous changes to operator screens. In one sense service has not been lost as the screen is still available; in another sense, it has as the screen is no longer accurate. These types of events may or not have occurred from making computing resources unavailable. They could just as easily have been caused by compromising the computing resources. There needs to be a clear way to describe the impacts when systems or facilities cannot perform their intended function because of intentional or unintentional cyber events.