root celery vs celery root

root celery and celery root both are nouns.

Word	Noun	Adjective	Verb	Adverb
root celery	Yes	No	No	No
celery root	Yes	No	No	No

As nouns, root celery and celery root are synonyms defined as:

root celery and celery root: grown for its thickened edible aromatic root

Other synonyms of root celery include Apium graveolens rapaceum, celeriac, knob celery, turnip-rooted celery.

root celery (noun)	celery root (noun)
grown for its thickened edible aromatic root	thickened edible aromatic root of a variety of celery plant
	grown for its thickened edible aromatic root