Republic of Belarus vs Byelorussia

Republic of Belarus and Byelorussia both are nouns.

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

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

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

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

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