celery root vs knob celery

celery root and knob celery both are nouns.

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

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

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

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

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