rock-salt

n [U] common salt as mined in crystal form 岩盐; 石盐.

robe, robin, Robinson Crusoe, robot, robot-arm, robotic, robotics, robust, robustly, robustness, rock, rock and roll (also ,rock 'n' `roll), rock salmon, rock'n'roll, rock-bottom, rock-cake, rock-climbing, rock-crystal, rock-garden, rock-plant, rock-steady, rocker, rockery, rocket, rocketry, rockiness, rocking-chair (also rocker), rocking-horse, rocky, rococo, rod, rode, rodent, rodeo, rodomontade, roe, roebuck, roentgen (also rontgen), Rogation Sunday, rogations,