Definition
The "mark of Cain" is a phrase referring to the biblical story of Cain and Abel. Cain murders his brother Abel, and God marks Cain as a sign of his sin and as a warning to others not to harm him. The mark isn't necessarily a physical brand but rather a sign of divine protection and punishment. It's often interpreted as a symbol of guilt, isolation, and being set apart. Consider it a burden of conscience and consequence. More broadly, it represents the stigma associated with committing a serious wrong.