infusorial earth

noun

in·​fu·​so·​ri·​al earth ˈin-fyü-ˈzȯr-ē-əl- 

-ˈsȯr-

: kieselguhr

Word History

Etymology

infusorial "relating to or containing infusorians," from New Latin Infusoria "group of minute organisms found in infusions of decaying matter" + -al entry 1 — more at infusorian

First Known Use

1868, in the meaning defined above