tomcat vs Felis domesticus

tomcat and Felis domesticus both are nouns.

Word	Noun	Adjective	Verb	Adverb
tomcat	Yes	No	No	No
Felis domesticus	Yes	No	No	No

As nouns, Felis domesticus is a hypernym of tomcat; that is, Felis domesticus is a word with a broader meaning than tomcat:

Other hypernyms of tomcat include domestic cat, Felis catus, house cat.

tomcat (noun)	Felis domesticus (noun)
male cat	any domesticated member of the genus Felis