weathercock vs weather vane

weathercock and weather vane both are nouns.

Word	Noun	Adjective	Verb	Adverb
weathercock	Yes	No	No	No
weather vane	Yes	No	No	No

As nouns, weather vane is a hypernym of weathercock; that is, weather vane is a word with a broader meaning than weathercock:

weathercock: weathervane with a vane in the form of a rooster
weather vane: mechanical device attached to an elevated structure; rotates freely to show the direction of the wind

Other hypernyms of weathercock include vane, weathervane, wind vane.

weathercock (noun)	weather vane (noun)
weathervane with a vane in the form of a rooster	mechanical device attached to an elevated structure; rotates freely to show the direction of the wind