pistachio tree vs pistachio

pistachio tree and pistachio both are nouns.

Word	Noun	Adjective	Verb	Adverb
pistachio tree	Yes	No	No	No
pistachio	Yes	No	No	No

As nouns, pistachio tree and pistachio are synonyms defined as:

pistachio tree and pistachio: small tree of southern Europe and Asia Minor bearing small hard-shelled nuts

Other synonyms of pistachio tree include Pistacia vera.

pistachio tree (noun)	pistachio (noun)
small tree of southern Europe and Asia Minor bearing small hard-shelled nuts	nut of Mediterranean trees having an edible green kernel
	small tree of southern Europe and Asia Minor bearing small hard-shelled nuts