The term MOAT WALL is composed of two words: MOAT and WALL. A MOAT is a deep, wide ditch that is usually filled with water and is built around a castle or other fortification as a defensive measure. A WALL is a structure made of stone, brick, or other materials, typically built along the perimeter of a building or other area for protection or privacy. Together, a MOAT and WALL form a formidable barrier to protect a castle or other structure from attack. The crossword solution ESCARP is a type of WALL that is built on the inner side of a MOAT. It is usually made of earth and is designed to prevent attackers from entering the MOAT.