rambutan tree vs rambutan

rambutan tree and rambutan both are nouns.

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

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

Other synonyms of rambutan tree include Nephelium lappaceum, rambotan.

rambutan tree (noun)	rambutan (noun)
Malayan tree bearing spiny red fruit	pleasantly acid bright red oval Malayan fruit covered with soft spines
	Malayan tree bearing spiny red fruit