gurnard vs sea robin

gurnard and sea robin both are nouns.

Word	Noun	Adjective	Verb	Adverb
gurnard	Yes	No	No	No
sea robin	Yes	No	No	No

As nouns, sea robin is a hyponym of gurnard; that is, sea robin is a word with a more specific, narrower meaning than gurnard:

gurnard: bottom-dwelling coastal fishes with spiny armored heads and fingerlike pectoral fins used for crawling along the sea bottom
sea robin: American gurnard; mostly found in bays and estuaries

Other hyponyms of gurnard include Trigla lucerna, tub gurnard, yellow gurnard, searobin.

gurnard (noun)	sea robin (noun)
bottom-dwelling coastal fishes with spiny armored heads and fingerlike pectoral fins used for crawling along the sea bottom	American gurnard; mostly found in bays and estuaries