Taiwan vs Formosa

Taiwan and Formosa both are nouns.

Word	Noun	Adjective	Verb	Adverb
Taiwan	Yes	No	No	No
Formosa	Yes	No	No	No

As nouns, Taiwan and Formosa are synonyms defined as:

Taiwan and Formosa: an island in southeastern Asia 100 miles off the coast of mainland China in the South China Sea

Taiwan (noun)	Formosa (noun)
a government on the island of Taiwan established in 1949 by Chiang Kai-shek after the conquest of mainland China by the Communists led by Mao Zedong	an island in southeastern Asia 100 miles off the coast of mainland China in the South China Sea
an island in southeastern Asia 100 miles off the coast of mainland China in the South China Sea