The individual values are defined as follows. Demand is
Unique, if it occurs only once within an observation period
Discontinuous, lumpy, sporadic, or highly volatile, if many observation periods with no or very little demand are interrupted by few periods with large, for example ten times higher demand, without recognizable regularity
Regular, if it can be calculated for every observation period according to a certain formula
Continuous or steady, if the demand is about the same in every observation period (e.g., daily)