The American Civil War has been known by numerous alternative names that reflect the historical, political, and cultural sensitivities of different groups and regions. Unlike some other civil wars, the conflict was not fought over control of a single government, but rather was fought to defeat or defend a secession movement. The combatants, armies, and battles of the war also had distinctive names used at the time and historically.

The following names have been, or are, used to describe the conflict itself, listed roughly by frequency of use. The first two names have seen enduring usage; the remaining names have been more isolated.

Civil War

The most common term for the conflict, it has been used by the overwhelming majority of reference books, scholarly journals, dictionaries, encyclopedias, popular histories, and mass media in the United States since the early 20th century.^[1] The National Park Service, the government organization entrusted by the United States Congress to preserve the battlefields of the war, uses this term. It is also the oldest term for the war. Writings of prominent men such as Jefferson Davis, Robert E. Lee, Ulysses S. Grant, William Tecumseh Sherman, P.G.T. Beauregard, Nathan Bedford Forrest, and Judah P. Benjamin used the term Civil War both before and during the conflict. Abraham Lincoln used it on multiple occasions.

English-speaking historians outside the United States usually refer to the conflict as the American Civil War or, less often, U.S. Civil War. These variations are seldom used in the United States except in cases in which the war might otherwise be confused with another historical event (e.g., the English Civil War).

War Between the States

This term was rarely used during the war but became common afterwards in the South.

• The Confederate government avoided the term "civil war" and referred in official documents to the "War between the Confederate States of America and the United States of America."^[2] There are a handful of known references during the war to "the war between the states."^[3]

• European diplomacy produced a similar formula for avoiding the phrase "civil war." Queen Victoria's proclamation of British neutrality referred to "hostilities ... between the Government of the United States of America and certain States styling themselves the Confederate States of America."^[2]

• After the war, the memoirs of former Confederate officials and veterans (e.g., Joseph E. Johnston, Raphael Semmes, and especially Alexander Stephens) commonly used the term "War Between the States." In 1898 the United Confederate Veterans formally endorsed the name.

• In the early twentieth century the United Daughters of the Confederacy led a campaign to promote the term "War Between the States" in the media and in public schools.

• Efforts to convince the United States Congress to adopt the term, beginning in 1913, were unsuccessful. Congress has never adopted an official name for the Civil War.

• The name "War Between the States" is inscribed on the Marine Corps memorial at Arlington National Cemetery.

• References to the "War Between the States" turn up in federal and state court documents from time to time. ^[4]

The names "Civil War" and "War Between the States" have been used jointly in some formal contexts.

• The war's centenary in the 1960s saw the creation of the Georgia Civil War Centennial Commission Commemorating the War Between the States.

• In 1994 the U.S. Postal Service issued commemorative stamps titled "The Civil War / The War Between the States."

War of the Rebellion

During and immediately after the war, U.S. officials and pro-Union writers often referred to Confederates as "Rebels" and to the war itself as "the Rebellion." In modern usage, however, the term "War of the Rebellion" usually refers only to the collection of documents compiled and published by the U.S. War Department as The War of the Rebellion: a Compilation of the Official Records of the Union and Confederate Armies, U.S. Government Printing Office, 1880–1901. This 70-volume collection is the chief source of historical documentation for those interested in Civil War research.