bitter pignut vs bitternut hickory

bitter pignut and bitternut hickory both are nouns.

Word	Noun	Adjective	Verb	Adverb
bitter pignut	Yes	No	No	No
bitternut hickory	Yes	No	No	No

As nouns, bitter pignut and bitternut hickory are synonyms defined as:

bitter pignut and bitternut hickory: hickory of the eastern United States having a leaves with 7 or 9 leaflets and thin-shelled very bitter nuts

Other synonyms of bitter pignut include bitter hickory, bitternut, Carya cordiformis, swamp hickory.

bitter pignut (noun)	bitternut hickory (noun)
hickory of the eastern United States having a leaves with 7 or 9 leaflets and thin-shelled very bitter nuts	hickory of the eastern United States having a leaves with 7 or 9 leaflets and thin-shelled very bitter nuts