rock gunnel vs gunnel

rock gunnel and gunnel both are nouns.

Word	Noun	Adjective	Verb	Adverb
rock gunnel	Yes	No	No	No
gunnel	Yes	No	No	No

As nouns, gunnel is a hypernym of rock gunnel; that is, gunnel is a word with a broader meaning than rock gunnel:

rock gunnel: slippery scaleless food fish of the northern Atlantic coastal waters
gunnel: small eellike fishes common in shallow waters of the northern Atlantic

Other hypernyms of rock gunnel include bracketed blenny.

rock gunnel (noun)	gunnel (noun)
slippery scaleless food fish of the northern Atlantic coastal waters	small eellike fishes common in shallow waters of the northern Atlantic
	wale at the top of the side of boat; topmost planking of a wooden vessel