bentonite
/bɛntənɪt/Definitions
1. noun
A type of clay that swells when exposed to water, used in drilling muds, cosmetics, and pharmaceuticals.
“The bentonite clay is mixed with water to create a face mask for skin care.”
2. verb
To treat or coat with bentonite, especially in drilling operations.
“The drilling company bentonited the well to prevent water infiltration.”