domestic cat vs Felis catus

domestic cat and Felis catus both are nouns.

Word	Noun	Adjective	Verb	Adverb
domestic cat	Yes	No	No	No
Felis catus	Yes	No	No	No

As nouns, domestic cat and Felis catus are synonyms defined as:

domestic cat and Felis catus: any domesticated member of the genus Felis

Other synonyms of domestic cat include Felis domesticus, house cat.

domestic cat (noun)	Felis catus (noun)
any domesticated member of the genus Felis	any domesticated member of the genus Felis