The South side of the American Civil War became its own nation, called the Confederate States of America, or the Confederacy for short, while the North remained the United States of America and was called the Union. The South was also called Dixie, a nod to the Mason-Dixon line.
In addition to having alternate names for the sides, the soldiers had nicknames as well. Union soldiers were individually called Yankees, Yanks and Federals and as a whole were referred to as "Billy Yank." Confederate soldiers were called Rebels and Rebs, or simply "Johnny Reb." Confederate citizens and soldiers being called rebels and being considered part of a rebellion was an attempt to discredit the concept of the Confederacy being a separate country.