German cockroach vs Blattella germanica

German cockroach and Blattella germanica both are nouns.

Word	Noun	Adjective	Verb	Adverb
German cockroach	Yes	No	No	No
Blattella germanica	Yes	No	No	No

As nouns, German cockroach and Blattella germanica are synonyms defined as:

German cockroach and Blattella germanica: small light-brown cockroach brought to United States from Europe; a common household pest

Other synonyms of German cockroach include Croton bug, crotonbug, water bug.

German cockroach (noun)	Blattella germanica (noun)
small light-brown cockroach brought to United States from Europe; a common household pest	small light-brown cockroach brought to United States from Europe; a common household pest