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cover crop

(Encyclopedia)cover crop, green temporary crop grown to prevent or reduce erosion and to improve the soil by building up its organic content. Green-manure crops, which are specifically grown for their organic conte...

gastric juice

(Encyclopedia)gastric juice, thin, strongly acidic (pH varying from 1 to 3), almost colorless liquid secreted by the glands in the lining of the stomach. Its essential constituents are the digestive enzymes pepsin ...

antifreeze

(Encyclopedia)antifreeze, substance added to a solvent to lower its freezing point. The solution formed is called an antifreeze mixture. Antifreeze is typically added to water in the cooling system of an internal-c...

stratification

(Encyclopedia)stratification (Lat.,=made in layers), layered structure formed by the deposition of sedimentary rocks. Changes between strata are interpreted as the result of fluctuations in the intensity and persis...

rood

(Encyclopedia)rood ro͞od [key], crucifix mounted above the entrance to the chancel and flanked by large figures of the Virgin and St. John, an almost invariable feature in the 14th- and 15th-century European churc...

filigree

(Encyclopedia)filigree fĭlˈĭgrē [key], ornamental work of fine gold or silver wire, often wrought into an openwork design and joined with matching solder and borax under the flame of the blowpipe. Filigree is u...

tanzanite

(Encyclopedia)tanzanite tănzănˈīt [key], beautiful gemstone discovered in 1967 in the Umba Valley near the Usambara Mts. in Tanzania, a precious variety of the mineral zoisite, a calcium aluminum silicate. Zois...

dolomite

(Encyclopedia)dolomite dōˈləmītˌ, dŏlˈə– [key]. 1 Mineral, calcium magnesium carbonate, CaMg (CO3)2. It is commonly crystalline and is white, gray, brown, or reddish in color with a vitreous to pearly lus...

mercury poisoning

(Encyclopedia)mercury poisoning, tissue damage resulting from exposure to more than trace amounts of the element mercury or its compounds. Elemental mercury (the silver liquid familiar from thermometers) is the mos...

molecular weight

(Encyclopedia)molecular weight, weight of a molecule of a substance expressed in atomic mass units (amu). The molecular weight may be calculated from the molecular formula of the substance; it is the sum of the ato...