limestone.

A sedimentary rock composed mainly of calcium carbonate, often from accumulated shells or other organic remains.

Use it for

Words that belong together

• limestone cliff
• limestone pavement
• weathered limestone

On the page

Rain had widened the cracks in the limestone.

The cave opened beneath a band of pale limestone.

Shell fragments were visible in the limestone at her feet.

Usage notes

Primary category: environment. Often pale but not always; caves and solution-worn surfaces are characteristic, not universal. Mass noun for material; limestones in geological discussion of types or formations.