mollusc
noun [ C ] mainly UK (US usually mollusk) uk/ˈmɒl.əsk/ us/ˈmɑː.ləsk/
软体动物
any animal that has a soft body, no spine, and is often covered with a shell. Many molluscs live in water.
Oysters are molluscs, as are snails and cuttlefish. 牡蛎是软体动物，蜗牛和乌贼也是。