A protective barrier is a structure or device designed to prevent access or damage from outside forces. The three crossword solutions for the term protective barrier are BERM (4 letters), RAMPART (7 letters), and DIKE (4 letters). A BERM is an embankment of earth that is used to protect against flooding or erosion. A RAMPART is a defensive wall of earth or stone built around a castle or other fortification. A DIKE is an artificial waterway or embankment, typically built to prevent flooding.