In′fu‐so″ri‐al (?), a.(Zoöl.) 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.