cliff brake vs fern

cliff brake and fern both are nouns.

Word	Noun	Adjective	Verb	Adverb
cliff brake	Yes	No	No	No
fern	Yes	No	No	No

As nouns, fern is a hypernym of cliff brake; that is, fern is a word with a broader meaning than cliff brake:

cliff brake: any of several small lithophytic ferns of tropical and warm temperate regions
fern: any of numerous flowerless and seedless vascular plants having true roots from a rhizome and fronds that uncurl upward; reproduce by spores

cliff brake (noun)	fern (noun)
any of several small lithophytic ferns of tropical and warm temperate regions	any of numerous flowerless and seedless vascular plants having true roots from a rhizome and fronds that uncurl upward; reproduce by spores