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Toltec

(Encyclopedia)Toltec tŏlˈtĕk [key], ancient civilization of Mexico. The name in Nahuatl means “master builders.” The Toltec formed a warrior aristocracy that gained ascendancy in the Valley of Mexico c.a.d. ...

coin

(Encyclopedia)coin, piece of metal, usually a disk of gold, silver, nickel, bronze, copper, aluminum, or a combination of such metals, stamped by authority of a government as a guarantee of its real or exchange val...

cold fusion

(Encyclopedia)cold fusion or low-temperature fusion, nuclear fusion of deuterium, an isotope of hydrogen, at or relatively near room temperature. Fusion, the reaction involved in the release of the destructive ener...

Greenville

(Encyclopedia)Greenville. 1 City (2020 pop. 29,670, seat of Washington co., W Miss., on Lake Ferguson, a deepwater harbor adjoining the Mississippi River; inc. ...

flame

(Encyclopedia)flame, phenomenon associated with the chemical reaction of a gas that has been heated above its kindling temperature with some other gas, usually atmospheric oxygen (see combustion). The heat and ligh...

silicate

(Encyclopedia)silicate, chemical compound containing silicon, oxygen, and one or more metals, e.g., aluminum, barium, beryllium, calcium, iron, magnesium, manganese, potassium, sodium, or zirconium. Silicates may b...

Bronze Age

(Encyclopedia)Bronze Age, period in the development of technology when metals were first used regularly in the manufacture of tools and weapons. Pure copper and bronze, an alloy of copper and tin, were used indiscr...

cesium

(Encyclopedia)cesium sēˈzēəm [key] [Lat.,=bluish gray], a metallic chemical element; symbol Cs; at. no. 55; at. wt. 132.90545; m.p. 28.4℃; b.p. 669.3℃; sp. gr. 1.873 at 20℃; valence +1. Cesium is a ductil...

magnesium

(Encyclopedia)magnesium măgnēˈzēəm, –zhəm [key], metallic chemical element; symbol Mg; at. no. 12; at. wt. 24.3050; m.p. about 648.8℃; b.p. about 1,090℃; sp. gr. 1.738 at 20℃; valence +2. In 1808, Sir...

metalwork

(Encyclopedia)metalwork. Copper, gold, and silver were probably fashioned into ornaments and amulets as early as the Neolithic period. Goldwork and silverwork have since employed the talents of leading artisans and...