rabbit ears vs tv-antenna

rabbit ears and tv-antenna both are nouns.

Word	Noun	Adjective	Verb	Adverb
rabbit ears	Yes	No	No	No
tv-antenna	Yes	No	No	No

As nouns, tv-antenna is a hypernym of rabbit ears; that is, tv-antenna is a word with a broader meaning than rabbit ears:

rabbit ears: an indoor TV antenna; consists of two extendible rods that form a V
tv-antenna: an omnidirectional antenna tuned to the broadcast frequencies assigned to television

Other hypernyms of rabbit ears include television antenna.

rabbit ears (noun)	tv-antenna (noun)
the long ears of a rabbit	an omnidirectional antenna tuned to the broadcast frequencies assigned to television
an indoor TV antenna; consists of two extendible rods that form a V