"Few wars have been referred to in quite so many ways as this one, and its various names reflect a wide range of attitudes toward the conflict. The official name given to it by the victorious Federal government is, of course, the Civil War, a term that came into use in 1861. In the Southern states, however, the terms used in 1861 included the Revolution, the Second War for Independence, and the War of Secession.
A variety of other names came into use during the war and in the decades following it, most of which reveal partiality to one side or the other, a tone of reconciliation, humor or an emphasis on some aspect of the conflict. These include the Great Fratricide, the War of Northern Aggression, the War for Constitutional Liberty, the War Between the States, the War Between the North and the South, the War for Southern Independence, the Second American Revolution, the War for States’ Rights, Mr. Lincoln’s War, the Southern Rebellion, the War for Southern Rights, the War of the Southern Planters, the War of the Rebellion, the War to Suppress Yankee Arrogance, the Brothers’ War, the Great Rebellion, the War for Nationality, the War for Southern Nationality, the War Against Slavery, the Civil War Between the States, the War of the Sixties, the War Against Northern Aggression, the Yankee Invasion, the War for Separation, the War for Abolition, the War for Union, the Confederate War, the War of the Southrons, the War for Southern Freedom, the War of the North and the South, the Lost Cause, the Late Unpleasantness, the late Friction, the Late Ruction, the Schism, the Uncivil War and, especially in the South in the years since it ended, simply as the War.
Overseas, the conflict was given still other names. For example, contemporary German writers refer to it as the North American War."
Hopefully I have included some names for the Civil War that you had not yet heard before — and if you know of any that I have missed please add to the list by posting a comment here!