In Jamaican Patois and Rastafarian culture, "Dread" (or "Dreadlocks") refers to:
Cultural significance: Dreadlocks symbolize a covenant with God (Nazirite vow, Numbers 6:5), African identity, resistance to Babylon (oppressive systems), and naturalness. Not all who wear locks are Rastas, and not all Rastas have locks—but the term "Dread" strongly implies both.
Usage: "Big up di dread dem" = respect to the Rastas/locked ones.