A prune is a dried plum, most commonly from the European plum tree. Not all plum species or varieties can be dried into prunes. Use of the term prune for fresh plums is obsolete except when applied to
Dried plums (prunes)
Raw plums that have not been dried into prunes
Prunes in chocolate with an almond in the middle
Moroccan-style tagine of lamb with prunes and almonds
A plum is a fruit of some species in Prunus subg. Prunus. Dried plums are usually called prunes.
African Rose plums (Japanese or Chinese plum)