water hickory vs bitter pecan

water hickory and bitter pecan both are nouns.

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

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

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

Other synonyms of water hickory include Carya aquatica, water bitternut.

water hickory (noun)	bitter pecan (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