Meaning of diatom

di•a•tom

Pronunciation: (dī'u-tum -tom"), [key]
— n.
  1. any of numerous microscopic, unicellular, marine or freshwater algae of the phylum Chrysophyta, having cell walls containing silica.
Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease.
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