diatom

Definitions of diatom
  1. noun
    microscopic unicellular marine or freshwater colonial alga having cell walls impregnated with silica
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    type of:
    phytoplankton
    photosynthetic or plant constituent of plankton; mainly unicellular algae
    alga, algae
    primitive chlorophyll-containing mainly aquatic eukaryotic organisms lacking true stems and roots and leaves
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