Home › Words › S › sourplumsourplumsourplum · noun — A kind of tree found in South East Africa (Ximenia afra).Definition from Wiktionary (CC BY-SA 3.0).EtymologyFrom sour + plum, probably in reference to the fact that the fruit resembles a plum and tastes sour.nounA kind of tree found in South East Africa (Ximenia afra).Definitions & examples from Wiktionary (CC BY-SA 3.0).