/blak"thawrn'/ , n.
1. a shrub or tree of the genus Crataegus, as C. calpodendron.
2. a walking stick made of a blackthorn tree or shrub.
3. Also called sloe . a much-branched, thorny, Old World shrub, Prunus spinosa, having white flowers and small plumlike fruits.
4. See pear haw .
[ 1350-1400; ME blak thorn. See BLACK, THORN ]