Does anyone remember when champagne produced in California was formally classified as ‘sparkling wine’? ‘Champagne’ is a technical classification for that which originates from the region of France for which it is named. That makes sense. The technical classifications of prune and plum formerly made sense also, even if not universally understood. Reclassification in 2001 ruined that.
Prune, Prunus domestica, is primarily a European freestone fruit. (The pits of freestone fruits separate from the ripening flesh.) They have firmer flesh than plum, so are more practical for canning and drying. They also have higher sugar content, so might be dried without sulfuring (which prevents molding). Darkly purple and rather oblong fresh prunes are less popular than dried prunes are.
Plum is primarily a Japanese cling fruit. (The pits of cling fruits remain firmly adhered to ripening flesh.) They are softer and juicier than prune, and contain less sugar, so are not as efficiently pitted and dried without sulfuring, or canned. Larger, rounder, more colorful and more richly flavored plums are instead best fresh. They might be bluish purple, purple, red, ruddy orange, yellow or green.
Nowadays, all prunes and plums are known collectively as plums. Dried prunes are just dried plums.
Tony Tomeo 
Hi Tony…good description…we live on the north side of the main French prune growing area…very lovely! They do like to soak prunes in Cognac over here!!
LikeLiked by 1 person
I think we used to know those as cordials. I do not remember. They were not just prunes though. They started with a layer of sweet cherries because they ripened first. (Tart cherries were not grown here. No one knows why.) A layer of prunes were added next because they ripened next. Apricots ripened immediately afterward, so were added next. (Apricots might have been prior to prunes.) Plums might have been added in there whenever they ripened, if they happened to be available. Finally, if available, nectarines or peaches were added on top. Booze were added with each layer to keep the whole mess submerged. plums and nectarines turned to mush and made the liquid more like a gravy.
LikeLike
I like the sound of this, Tony!
LikeLiked by 1 person
The aroma is even better than the sound! Actually, I think the aroma is even better than the flavor. You know, I never actually ate much of it. Small amounts of it were added on top of deserts.
LikeLiked by 1 person
It’s the same with my sweetheart’s sloe gin. He likes making it, but we rarely drink any.
LikeLiked by 1 person
I grew up with stewed prunes, but when I purchased some to stew a couple of years ago, they weren’t nearly as good as I remembered. It might just be that I had real prunes as a kid, and dried plums more recently. Interesting.
LikeLiked by 1 person
It is difficult to know what is what anymore. Because the distinction between the two is so vague now, people dry Japanese plums, which turn to icky goo!
LikeLike
I had no idea that prunes and plums were not the same! I love them both, though. My grandmother used to make a kind of tart meat stew with what she called “sour plums”, which I think are known as Damsons. You don’t see them in the stores, but sometimes at a farmers market you can find them.
LikeLiked by 1 person
Damsoms were grown here too, although not as commonly as the French or Italian prunes. French prunes were the most common. Damsoms might have been grown more for prune juice and canning than drying. If I remember correctly, what we knew as stewed pruned were the Damsoms. Plums were popular in home gardens, but not in orchards. I like them anyway because I grew up with them.
LikeLike
Now that you mention it, I think my grandmother’s “sour plums” might have been Italian plums.
LikeLiked by 1 person