War between the States vs United States Civil War

War between the States and United States Civil War both are nouns.

Word	Noun	Adjective	Verb	Adverb
War between the States	Yes	No	No	No
United States Civil War	Yes	No	No	No

As nouns, War between the States and United States Civil War are synonyms defined as:

War between the States and United States Civil War: civil war in the United States between the North and the South; 1861-1865

Other synonyms of War between the States include American Civil War.

War between the States (noun)	United States Civil War (noun)
civil war in the United States between the North and the South; 1861-1865	civil war in the United States between the North and the South; 1861-1865