| rare-earth screen | An intensifying screen made of a rare-earth oxide phosphor, more efficient than calcium tungstate, especially at the higher kilovoltages used in modern radiography. (05 Mar 2000) |
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| metals, alkaline earth | Metals that constitute the group IIa in the periodic table. (12 Dec 1998) |
| metals, rare earth | Elements of group IIIb of the periodic table from lanthanum, atomic number 57, to and including lutetium, atomic number 71. (12 Dec 1998) |
| 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) |
| earth | 1. <astronomy> Planet that is the third in order from the sun. It is one of the four inner or terrestrial planets of the solar system. 2. The softer inorganic matter composing part of the surface of the globe, in distinction from the firm rock; soil of all kinds, including gravel, clay, loam, and the like; sometimes, soil favorable to the growth of plants; the visible surface of the globe; the ground; as, loose earth; rich earth. "Give him a little earth for charity." (Shak) 3. <chemistry> Any earthy-looking metallic oxide, as alumina, glucina, zirconia, yttria, and thoria. A similar oxide, having a slight alkaline reaction, as lime, magnesia, strontia, baryta. 4. Earth is used either adjectively or in combination to form compound words; as, earth apple or earth-apple; earth metal or earth-metal; earth closet or earth-closet. Adamic earth, Bitter earth, Bog earth, Chian earth, etc. See Adamic, Bitter, etc. Alkaline earths. See Alkaline. Earth apple. Origin: AS. Eore; akin to OS. Ertha, OFries. Irthe, D. Aarde, OHG. Erda, G. Erde, Icel. Jor, Sw. & Dan. Jord, Goth. Airpa, OHG. Ero, Gr, adv, to earth, and perh. To E. Ear to plow. Source: Websters Dictionary (25 Jun 1999) |
| earth flax | <chemical> A variety of asbestus. See Amianthus. Source: Websters Dictionary (01 Mar 1998) |
| earth-tongue | <botany> A fungus of the genus Geoglossum. Source: Websters Dictionary (01 Mar 1998) |
| earth wax | A natural mixture of hydrocarbons of high molecular weight; a substitute for beeswax, also used in dentistry for impressions. Synonym: cerin, cerosin, earth wax, mineral wax, purified ozokerite. (05 Mar 2000) |
| fuller's earth | An amorphous variety of kaolin of varying composition, containing an aluminum magnesium silicate. The name is derived from an ancient process of cleansing or "fulling" wool to remove the oil and dirt particles with a water slurry of earth or clay. A refined clay sometimes used as a dusting powder or applied moistened with water as a form of poultice. Currently refers to any clay that can be used for the purpose of decolorizing in oil refining. Used as decoloriser for oils and other liquids, filtering medium, filler for rubber, and in agricultural formulations. Origin: fr. Fulling, an old process of cleaning wool, with earth or clay (05 Mar 2000) |