Definitions

1. noun

The internal shell of a cuttlefish, used as a buoyancy device.

“The cuttlebone of the cuttlefish helped it stay afloat in the water.”

2. noun

A lightweight, porous structure used in crafts and decorations, often made from sponges or other materials, resembling the internal shell of a cuttlefish.

“The artist used cuttlebone to create a unique mobile for the store window.”