Riprap is a term that refers to a type of hard, durable material used for erosion control, usually in bodies of water. Synonyms for riprap include rock armour, gabion, rubble, and stone. Rock armour refers to large rocks placed at the base of a shoreline to prevent erosion from waves. Gabions refer to wire baskets that are filled with rocks, acting as a barrier for water flow. Rubble is a term used for broken or rough stones that are used for fill or construction work. Stone is a broad term that encompasses various types of rocks used for construction purposes. Each of these synonyms for riprap can be effectively used for erosion control and to provide stability to bodies of water.