a small rosaceous tree, Prunus domestica instititia (or P. instititia), cultivated for its blue-black edible plumlike fruit and probably derived from the bullace
See also plum1 (sense 1)
2.
the fruit of this tree
Word origin
C14: from Latin prūnum Damascēnum Damascus plum
damson in American English
(ˈdæmzən; ˈdæmsən)
noun
1.
a variety of small, purple plum; bullace
2.
the prunus tree (Prunus domestica var. insititia) on which it grows
Word origin
ME damasin < OFr damascene, plum of Damascus < L Damascenus, lit., of Damascus