Marne River vs Second Battle of the Marne

Marne River and Second Battle of the Marne both are nouns.

Word	Noun	Adjective	Verb	Adverb
Marne River	Yes	No	No	No
Second Battle of the Marne	Yes	No	No	No

As nouns, Marne River and Second Battle of the Marne are synonyms defined as:

Marne River and Second Battle of the Marne: a World War I battle in northwestern France where the Allies defeated the Germans in 1918

Other synonyms of Marne River include Battle of the Marne, Belleau Wood, Chateau-Thierry.

Marne River (noun)	Second Battle of the Marne (noun)
a World War I battle in northwestern France where the Allies defeated the Germans in 1918	a World War I battle in northwestern France where the Allies defeated the Germans in 1918