1. plural of grayback; body lice, especially those that infested soldiers during wars
Usage: historical; informal
2. plural of grayback; Confederate soldiers during the American Civil War (from the color of their uniforms)
Usage: historical; informal
3. plural of grayback; various birds or fish with gray backs, such as certain types of whales or seabirds
Usage: zoology

Examples

• Soldiers in the trenches complained constantly about graybacks infesting their clothing.
• The graybacks launched a surprise attack at dawn.
• During the Civil War, Union troops sometimes referred to their enemies as graybacks.
• The ship's crew spotted a pod of graybacks swimming alongside the vessel.
• Hygiene was difficult in the camps, and graybacks were a persistent problem for all soldiers.