Republic of Belarus vs Belorussia

Republic of Belarus and Belorussia both are nouns.

Word	Noun	Adjective	Verb	Adverb
Republic of Belarus	Yes	No	No	No
Belorussia	Yes	No	No	No

As nouns, Republic of Belarus and Belorussia are synonyms defined as:

Republic of Belarus and Belorussia: a landlocked republic in eastern Europe; formerly a European soviet

Other synonyms of Republic of Belarus include Belarus, Byelarus, Byelorussia, White Russia.

Republic of Belarus (noun)	Belorussia (noun)
a landlocked republic in eastern Europe; formerly a European soviet	a landlocked republic in eastern Europe; formerly a European soviet