Meaning

noun wild plum of northeastern United States having dark purple fruits with yellow flesh

noun a thorny Eurasian bush with plumlike fruits

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

originFrom Middle English slo, sla, sloo, from Old English slā, slāh, from Proto-West Germanic *slaihā, from Proto-Germanic *slaihǭ, *slaihwō, from Proto-Indo-European *(s)leh₃y- (“bluish”). Doublet of Sliwa.

Etymology from Wiktionary, CC BY-SA 3.0