triggerfish vs oldwife

triggerfish and oldwife both are nouns.

Word	Noun	Adjective	Verb	Adverb
triggerfish	Yes	No	No	No
oldwife	Yes	No	No	No

As nouns, oldwife is a hyponym of triggerfish; that is, oldwife is a word with a more specific, narrower meaning than triggerfish:

triggerfish: any of numerous compressed deep-bodied tropical fishes with sandpapery skin and erectile spines in the first dorsal fin
oldwife: tropical Atlantic fish

Other hyponyms of triggerfish include Balistes vetula, Bessy cerca, oldwench, queen triggerfish.

triggerfish (noun)	oldwife (noun)
any of numerous compressed deep-bodied tropical fishes with sandpapery skin and erectile spines in the first dorsal fin	tropical Atlantic fish
	a common long-tailed sea duck of the northern parts of the United States