[dahy-uh-tuh
m -tom] 
| any of numerous microscopic, unicellular, marine or freshwater algae of the phylum Chrysophyta, having cell walls containing silica. |
| di·a·tom (dī'ə-tŏm') n. Any of various microscopic one-celled or colonial algae of the class Bacillariophyceae, having cell walls of silica consisting of two interlocking symmetrical valves. [New Latin diatoma, from Greek diatomos, cut in half, from diatemnein, to cut in half : dia-, dia- + temnein, to cut; see tem- in Indo-European roots.] |
| 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. |