bitter pecan vs water bitternut

bitter pecan and water bitternut both are nouns.

Word	Noun	Adjective	Verb	Adverb
bitter pecan	Yes	No	No	No
water bitternut	Yes	No	No	No

As nouns, bitter pecan and water bitternut are synonyms defined as:

bitter pecan and water bitternut: hickory of southern United States having many narrow leaflets and rather bitter nuts

Other synonyms of bitter pecan include Carya aquatica, water hickory.

bitter pecan (noun)	water bitternut (noun)
hickory of southern United States having many narrow leaflets and rather bitter nuts	hickory of southern United States having many narrow leaflets and rather bitter nuts