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ocean

(Encyclopedia)ocean, interconnected mass of saltwater covering 70.78% of the surface of the earth, often called the world ocean. It is subdivided into four (or five) major units that are separated from each other i...

Gell-Mann, Murray

(Encyclopedia)Gell-Mann, Murray gĕlˈ-män [key], 1929–2019, American theoretical physicist, b. New York City, grad. Yale 1948, Ph.D. Massachusetts Institute of Technology, 1951. He was associated with the Univ....

Vehmgericht

(Encyclopedia)Vehmgericht fāˈmĭk [key], in medieval Germany, a type of criminal tribunal. The inability of the Holy Roman emperors to exercise effective central control over their lands and the extensive feudal ...

Appalachian Mountains

(Encyclopedia)Appalachian Mountains ăpəlāˈchən, –chēən, –lăchˈ– [key], mountain system of E North America, extending in a broad belt c.1,600 mi (2,570 km) SW from the Gaspé Peninsula in Quebec prov....

mucilage

(Encyclopedia)mucilage myo͞oˈsəlĭj [key], thick, glutinous substance, related to the natural gums, comprised usually of protein, polysaccharides, and uranides. It swells but does not dissolve in water. Mucilage...

cofferdam

(Encyclopedia)cofferdam, temporary barrier for excluding water from an area that is normally submerged. Made commonly of wood, steel, or concrete sheet piling (see pile), cofferdams are used in constructing the fou...

All-American Canal

(Encyclopedia)All-American Canal, 80 mi (129 km) long, SE Calif.; part of the federal irrigation system of the Hoover Dam. Built between 1934 and 1940 across the Colorado Desert, the canal is entirely within the Un...

heat exhaustion

(Encyclopedia)heat exhaustion, condition caused by overexposure to sunlight or another heat source and resulting in dehydration and salt depletion, also known as heat prostration. The symptoms are severe headaches,...

calcium carbonate

(Encyclopedia)calcium carbonate, CaCO3, white chemical compound that is the most common nonsiliceous mineral. It occurs in two crystal forms: calcite, which is hexagonal, and aragonite, which is rhombohedral. Calci...

periwinkle, in zoology

(Encyclopedia)periwinkle, any of a group of marine gastropod mollusks having conical, spiral shells. Periwinkles feed on algae and seaweed. They are found at the water's edge; out of water, they resist drying by cl...