|diatom (ˈdaɪətəm, -ˌtɒm)|
|See also diatomite any microscopic unicellular alga of the phylum Bacillariophyta, occurring in marine or fresh water singly or in colonies, each cell having a cell wall made of two halves and impregnated with silica|
|[C19: from New Latin Diatoma (genus name), from Greek diatomos cut in two, from diatemnein to cut through, from |
|a gadget; dingus; thingumbob.|
|an arrangement of five objects, as trees, in a square or rectangle, one at each corner and one in the middle.|
|diatom (dī'ə-tŏm') Pronunciation Key
Any of various microscopic protists of the phylum Bacillariophyta that live in both fresh and marine water, have hard bivalve shells (called frustules) composed mostly of silica, and often live in colonies. Most diatoms can perform photosynthesis. They make up a large portion of the marine plankton and are an important food source for many aquatic animals. The skeletal remains of diatoms are the main constituent of diatomite.