An absorbent aluminum silicate clay formed from volcanic ash and used in various adhesives, cements, and ceramic fillers.
A porous clay consisting mainly of the mineral montmorillonite, which swells greatly when it absorbs water.
Origin of bentonite
- After Benton Formation of the Rock Creek district in eastern Wyoming
From American Heritage Dictionary of the English Language, 5th Edition
- From Benton + -ite, after the place it was first mined: Fort Benton, Montana.