Why was the South Considered the Confederacy during the Civil War?

I was thinking last night and I wondered why was the South the Confederacy and the North the Union during the Civil War. Why did each region take on these distinct labels. As I pondered this it was clear why the North was the Union. After all, the United States of America had come together to form a perfect union. The North was united. Easy enough. But what about the South?

I looked up the word Confederate and it can mean to be in a league, alliance or conspiracy. When the Southern States seceded from the Union they formed an alliance and because they were against the Union they were in a conspiracy together. Another definition of confederate is an accomplice, especially in a mischievous or criminal act. Because the Southern States were pulling apart from the Northern States it was viewed as a crime against the government. Thus their banning together was illegal.

Which states comprised the Confederacy? South Carolina (seceded Dec. 20, 1860), Mississippi (Jan. 9, 1861), Florida (Jan. 10, 1861), Alabama (Jan. 11, 1861), Georgia (Jan. 19, 1861), Louisiana (Jan. 26, 1861), Texas (Feb. 1, 1861) [Note: these seven states seceded before Lincoln took office on March 4, 1861], Virginia (April 17, 1861, but ratified by voters May 23, 1861), Arkansas (May 6, 1861), Tennessee (May 7, 1861, but ratified by voters June 8, 1861), North Carolina (May 20, 1861) [Note: the last four states seceded after the attack on Fort Sumter April 12, 1861 which began the Civil War and Lincoln called for troops on April 15, 1861.

The Confederate States of America existed from 1861-1865. Jefferson Davis was elected as their provisional President on February 18, 1861 and he served in this position until the end in 1865.