tabby cat vs house cat

tabby cat and house cat both are nouns.

Word	Noun	Adjective	Verb	Adverb
tabby cat	Yes	No	No	No
house cat	Yes	No	No	No

As nouns, house cat is a hypernym of tabby cat; that is, house cat is a word with a broader meaning than tabby cat:

Other hypernyms of tabby cat include domestic cat, Felis catus, Felis domesticus.

tabby cat (noun)	house cat (noun)
a cat with a grey or tawny coat mottled with black	any domesticated member of the genus Felis