greyback n 1: `Johnny' was applied as a nickname for Confederate soldiers by the Federal soldiers in the American Civil War; `greyback' derived from their grey Confederate uniforms [syn: {Rebel}, {Reb}, {Johnny Reb}, {Johnny}, {greyback}] 2: a dowitcher with a grey back [syn: {greyback}, {grayback}, {Limnodromus griseus}] 3: a sandpiper that breeds in the Arctic and winters in the southern hemisphere [syn: {knot}, {greyback}, {grayback}, {Calidris canutus}]