celeriac vs herbaceous plant

celeriac and herbaceous plant both are nouns.

Word	Noun	Adjective	Verb	Adverb
celeriac	Yes	No	No	No
herbaceous plant	Yes	No	No	No

As nouns, herbaceous plant is a hypernym of celeriac; that is, herbaceous plant is a word with a broader meaning than celeriac:

celeriac: grown for its thickened edible aromatic root
herbaceous plant: a plant lacking a permanent woody stem; many are flowering garden plants or potherbs; some having medicinal properties; some are pests

Other hypernyms of celeriac include herb.

celeriac (noun)	herbaceous plant (noun)
thickened edible aromatic root of a variety of celery plant	a plant lacking a permanent woody stem; many are flowering garden plants or potherbs; some having medicinal properties; some are pests
grown for its thickened edible aromatic root