"It was not a "Civil War", as it was not fought between two parties within the same government.

"It was not a "War of Secession", for the Southern States seceded without a thought of war. The right of a State to secede had never been questioned.

"It was not a "War of Rebellion" for sovereign, independent States, co-equal, can not rebel against each other.

"It was a "War between the States", because twenty-two non-seceding States made war upon eleven seceding States to force them back into the Union of States. It was not until after the surrender of 1865 that secession was decided to be unconstitutional."