American persimmon vs persimmon

American persimmon and persimmon both are nouns.

Word	Noun	Adjective	Verb	Adverb
American persimmon	Yes	No	No	No
persimmon	Yes	No	No	No

As nouns, persimmon is a hypernym of American persimmon; that is, persimmon is a word with a broader meaning than American persimmon:

American persimmon: medium-sized tree of dry woodlands in the southern and eastern United States bearing yellow or orange very astringent fruit that is edible when fully ripe
persimmon: any of several tropical trees of the genus Diospyros

Other hypernyms of American persimmon include persimmon tree.

American persimmon (noun)	persimmon (noun)
medium-sized tree of dry woodlands in the southern and eastern United States bearing yellow or orange very astringent fruit that is edible when fully ripe	orange fruit resembling a plum; edible when fully ripe
	any of several tropical trees of the genus Diospyros