Any of the microscopic unicellular or colonial algae constituting the class Bacillarieae. They have a silicified cell wall, which persists as a skeleton after death and forms kieselguhr (loose or porous diatomite). Diatoms occur abundantly in fresh and salt waters, in soil, and as fossils. They form a large part of the Plankton.
DIATOM
Meaning of DIATOM in English
Environmental engineering English vocabulary. Английский словарь экологического инжиниринга. 2012