damson plum tree vs damson plum

damson plum tree and damson plum both are nouns.

Word	Noun	Adjective	Verb	Adverb
damson plum tree	Yes	No	No	No
damson plum	Yes	No	No	No

As nouns, damson plum tree and damson plum are synonyms defined as:

damson plum tree and damson plum: plum tree long cultivated for its edible fruit

Other synonyms of damson plum tree include Prunus domestica insititia.

damson plum tree (noun)	damson plum (noun)
plum tree long cultivated for its edible fruit	dark purple plum of the damson tree
	plum tree long cultivated for its edible fruit
	tropical American timber tree with dark hard heavy wood and small plumlike purple fruit