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Alexandria, cities, United States

(Encyclopedia)Alexandria. 1 City (2020 pop. 45,275), seat of Rapides parish, central La., on the Red River; inc. 1818. It is a trade, rail, and medical center for a rich agricultural and timber area. ...

ultrasonics

(Encyclopedia)ultrasonics, study and application of the energy of sound waves vibrating at frequencies greater than 20,000 cycles per second, i.e., beyond the range of human hearing. The application of sound energy...

Raoult's law

(Encyclopedia)Raoult's law räo͞olzˈ [key] [for F. M. Raoult, a French physicist and chemist] states that the addition of solute to a liquid lessens the tendency for the liquid to become a solid or a gas, i.e., r...

eyeglasses

(Encyclopedia)eyeglasses or spectacles, instrument or device for aiding and correcting defective sight. Eyeglasses usually consist of a pair of lenses mounted in a frame to hold them in position before the eyes. Th...

relocation center

(Encyclopedia)relocation center, in U.S. history, camp in which Japanese and Japanese-Americans were interned during World War II. Fearing a Japanese invasion, the military leaders, under authority of an executive ...

berkelium

(Encyclopedia)berkelium bûrˈklēəm [key] [from Berkeley], artificially produced radioactive chemical element; symbol Bk; at. no. 97; mass no. of most stable isotope 247; m.p. about 1,050℃; b.p. about 2,590℃;...

megachurch

(Encyclopedia)megachurch, large Protestant church with an average weekly attendance of 2,000 or more; relatively uncommon until after 1970. In the United States, where most megachurches are located, there were more...

integrated circuit

(Encyclopedia)integrated circuit (IC), electronic circuit built on a semiconductor substrate, usually one of single-crystal silicon. The circuit, often called a chip, is packaged in a hermetically sealed case or a ...

Oporto

(Encyclopedia)Oporto o͝opôrˈtō [key], Port. Pôrto, city (1991 pop. 310,600), capital of Porto dist. and Douro Litoral, NW Portugal, near the mouth of the Douro River. It is Portugal's second largest city, afte...

clock

(Encyclopedia)CE5 A pendulum clock: Weight-driven clock mechanism clock, instrument for measuring and indicating time. Predecessors of the clock were the sundial, the hourglass, and the clepsydra. See also watc...