A nickname bestowed by Southerners, during the Civil War, upon their opponents of the North, whose uniform was blue; also BOYS IN BLUE, YANKS, etc. The Southerners, on the other hand, received such names as THE SECESH, REBS, and JOHNNY REBS, the latter being sometimes shortened to JOHNNIES. The grey uniform of the Confederates likewise caused them to be styled BOYS IN GREY, and GREYBACKS.
1883. Daily Telegraph, Feb. 9, p. 5, col. 4. The Confederate armies during the great Civil War in America … were known … as ‘Greybacks,’ whereas their Federal opponents, from the light-azure gaberdines which they wore, were dubbed ‘BLUE-BELLIES.’
