Byelarus vs Byelorussia

Byelarus and Byelorussia both are nouns.

Word	Noun	Adjective	Verb	Adverb
Byelarus	Yes	No	No	No
Byelorussia	Yes	No	No	No

As nouns, Byelarus and Byelorussia are synonyms defined as:

Byelarus and Byelorussia: a landlocked republic in eastern Europe; formerly a European soviet

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

Byelarus (noun)	Byelorussia (noun)
a landlocked republic in eastern Europe; formerly a European soviet	a landlocked republic in eastern Europe; formerly a European soviet