To Stephan and anyone else still interested in this discussion.
You misunderstand my intentions and assertions. After you presented your dictionary definitions I did not question the correctness of those definitions just where the usage was being employed. I never assumed that my belief that this usage was limited to the less knowledgeable public was correct, which is why I asked for input from other members. I was obviously trying to communicate my own uncertainty.
I find your tone unnecessarily combative and can only assume that my original posting appeared the same to you for which I apologize.
As far as commercial growers in CA and how they use the word prune, I suspect that the reason for it is that the vast majority of their product has been used for drying. If their product was primarily used fresh they might have a different usage. California's fresh crop of plums is primarily Japanese types, I believe, so it is logical that their usage would evolve to this shorthand. This is just a guess, and I welcome any contradictory information. I don't have a lot of ego investment here. Honest!