(zoology) The sac in which the shell of a mollusc is secreted during development; (now especially) the fold of mantle in which a cephalopod secretes its pen or gladius.

Synonym of helmet snail

A Caribbean gastropod marked with figures resembling music notation.

A sea snail of the genus Charonia

A member of the genus Conus.

(historical) A cockleshell used as a sign that one had visited the Holy Land.

Sand consisting mainly of fragments of shells, and often containing a small proportion of organic matter.

plural of shell road

(US) A road with a bed or other layer made from shells.

(geology) A layer of mollusc shells