In`fu*so"ri*al (?), a. Zool.
Belonging to the Infusoria; composed of, or containing, Infusoria; as, infusorial earth.
Infusorial earth Geol., a deposit of fine, usually white, siliceous material, composed mainly of the shells of the microscopic plants called diatoms. It is used in polishing powder, and in the manufacture of dynamite.<-- = kieselguhr -->
© Webster 1913.