Marmara vs Sea of Marmora

Marmara and Sea of Marmora both are nouns.

Word	Noun	Adjective	Verb	Adverb
Marmara	Yes	No	No	No
Sea of Marmora	Yes	No	No	No

As nouns, Marmara and Sea of Marmora are synonyms defined as:

Marmara and Sea of Marmora: an inland sea in northwestern Turkey; linked to the Black Sea by the Bosporus and linked to the Aegean by the Dardanelles

Other synonyms of Marmara include Marmara Denizi, Marmora, Sea of Marmara.

Marmara (noun)	Sea of Marmora (noun)
an inland sea in northwestern Turkey; linked to the Black Sea by the Bosporus and linked to the Aegean by the Dardanelles	an inland sea in northwestern Turkey; linked to the Black Sea by the Bosporus and linked to the Aegean by the Dardanelles