| diatom | Algae of the division Bacillariophyta. They are largely unicellular and are characterised by having cell walls of hydrated silica embedded in an organic matrix. The cell walls are formed in two halves that fit together like the lid and base of a pillbox and often have elaborate patterns formed by pores. Diatoms are very abundant in marine and freshwater plankton. Deposits of the cell walls form diatomaceous or siliceous earths. (18 Nov 1997) |
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| diatomaceous | Pertaining to diatoms or their fossil remains. (05 Mar 2000) |
| diatomaceous earth | A type of silica-rich dirt which is soft, fine-grained, porous, light-coloured, and composed of the skeletons of diatoms (one-celled marine organisms with skeletons based on silicon). It is used as a filter. (09 Oct 1997) |
| diatomic | <chemistry> Containing two atoms. Having two replaceable atoms or radicals. Origin: Pref. Di- + atomic. Source: Websters Dictionary (01 Mar 1998) |
| diatomous | <chemical> Having a single, distinct, diagonal cleavage; said of crystals. Origin: Gr. Cut through, fr. To cut through; through + to cut. Cf. Diatom. Source: Websters Dictionary (01 Mar 1998) |
| diatoms | Microscopic unicellular algae. most are aquatic, being found in fresh, brackish, and salt water. Diatoms are noted for the symmetry and sculpturing of their siliceous cell walls. (12 Dec 1998) |