The term Japanese Apricot is used to refer to three different species of trees and their fruits. The first is the Mei (3 letters), which is a type of Prunus mume tree that produces small, round fruits with a sweet-tart flavor. The second is the Ume (3 letters), which is a type of Prunus mume tree that produces larger, oval-shaped fruits with a sour taste. The third is the Mume (4 letters), which is a type of Prunus mume tree that produces large, round fruits with a sweet-tart flavor. All three species of trees are native to Japan and are widely cultivated for their edible fruits.