an aquatic shellfish (generally limited to mollusks with calcareous shells such as clams or snails, and excluding crustaceans such as shrimp or crabs)

shellfish poison

Babylonia japonica: the Japanese babylon or Japanese ivory shell

shell / shellfish

Kyūjitai form of 貝殻: shell; seashell

a Triton's trumpet (Charonia tritonis) shell used in ancient times as a horn to signal troop movements

a Japanese cockle, an egg cockle: an edible marine bivalve mollusc of family Cardiidae, species Fulvia mutica

cone snail, cone shell (Conidae)

a nautilus

kai-awase (a Heian period game involving matching two pieces of a clamshell) / (slang) tribadism