hydraulic cement(n = noun.substance) portland cement - a cement that hardens under water; made by heating limestone and clay in a kiln and pulverizing the result;
is a kind of cement

cement, cement mixer, cement steel, hydraulic, hydraulic brake, hydraulic brake cylinder, hydraulic brakes, hydraulic engineering, hydraulic press, hydraulic pump, hydraulic ram, hydraulic system, hydraulic transmission, hydraulic transmission system, portland cement, rubber cement, water cement