This word is acceptable for play in the US & UK dictionaries that are being used in the following games:

• Lexulous
• Wordscraper
• Wordosaur

n. A fine, powdered diatomaceous earth used in industry as a filler, a filtering agent, an absorbent, a clarifier, and an insulator. Also called kieselguhr.

n. A fine, powdery earth formed from the skeletons of diatoms

n. Diatomaceous earth; infusorial earth.

n. a light soil consisting of siliceous diatom remains and often used as a filtering material

"These materials (such as diatomite, pumice, expanded clay and shale, etc.) may be used in place of perlite without losing any of the benefits that perlite provides."

ground    earth    filter   

kieselguhr    diatomaceous earth