sloe

(noun) wild plum of northeastern United States having dark purple fruits with yellow flesh. Synonyms: Allegheny plum, Alleghany plum, Prunus alleghaniensis.

(noun) a thorny Eurasian bush with plumlike fruits. Synonyms: blackthorn, Prunus spinosa.

(noun) small sour dark purple fruit of especially the Allegheny plum bush.