horse-plum

Century Dictionary and Cyclopedia

1. n. A small red plum which is regarded as a variety of Prunus domestica. Also called horse-jag, horse-jug.
2. n. The wild plum, Prunus Americana. The fruit, when fully ripe, is sweet and edible, and the tree is frequently cultivated either for its fruit or as a stock on which to graft the varieties of the domestic plum.