# shell sac

> English word · Noun

## Definitions
1. 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.

## Source
Compiled from Wiktionary via kaikki.org (CC BY-SA). Data vintage: 2026-05-06.
Canonical page: https://plainspell.com/en/word/shell-sac