falcon vs gerfalcon

falcon and gerfalcon both are nouns.

Word	Noun	Adjective	Verb	Adverb
falcon	Yes	No	Yes	No
gerfalcon	Yes	No	No	No

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

falcon: diurnal birds of prey having long pointed powerful wings adapted for swift flight
gerfalcon: large and rare Arctic falcon having white and dark color phases

falcon (noun)	gerfalcon (noun)
diurnal birds of prey having long pointed powerful wings adapted for swift flight	large and rare Arctic falcon having white and dark color phases

falcon (verb)	gerfalcon (verb)
hunt with falcons