brown hickory vs pignut

brown hickory and pignut both are nouns.

Word	Noun	Adjective	Verb	Adverb
brown hickory	Yes	No	No	No
pignut	Yes	No	No	No

As nouns, brown hickory and pignut are synonyms defined as:

Other synonyms of brown hickory include black hickory, Carya glabra, pignut hickory.

brown hickory (noun)	pignut (noun)
an American hickory tree having bitter nuts	an American hickory tree having bitter nuts