yellow dock vs bitter dock

yellow dock and bitter dock both are nouns.

Word	Noun	Adjective	Verb	Adverb
yellow dock	Yes	No	No	No
bitter dock	Yes	No	No	No

As nouns, yellow dock and bitter dock are synonyms defined as:

yellow dock and bitter dock: European dock with broad obtuse leaves and bitter rootstock common as a weed in North America

Other synonyms of yellow dock include broad-leaved dock, Rumex obtusifolius.

yellow dock (noun)	bitter dock (noun)
European dock with broad obtuse leaves and bitter rootstock common as a weed in North America	European dock with broad obtuse leaves and bitter rootstock common as a weed in North America