celery root vs celery root

celery root and celery root both are nouns.

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

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