when a phenomenon is described an random does a random mean that for an individual occurrence of the phenomenon, the outcome is unpredictable, but there is a long-run distribution of outcomes?

Yes, when a phenomenon is described as random, it means that for each individual occurrence or event, the outcome is unpredictable or uncertain. However, over a sufficiently large number of occurrences, there tends to be a long-run distribution or pattern of outcomes. This means that while any particular outcome may be uncertain, the overall behavior or statistical properties of the phenomenon can be understood or predicted in terms of probabilities. This is the basis of probability theory and statistics in the study of random phenomena.