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relativity

(Encyclopedia)relativity, physical theory, introduced by Albert Einstein, that discards the concept of absolute motion and instead treats only relative motion between two systems or frames of reference. One consequ...

prostitution

(Encyclopedia)prostitution, act of granting sexual access for payment. Although most commonly conducted by females for males, it may be performed by females or males for either females or males. Prostitution in A...

periodic table

(Encyclopedia)CE5 periodic table, chart of the elements arranged according to the periodic law discovered by Dmitri I. Mendeleev and revised by Henry G. J. Moseley. In the periodic table the elements are arrange...

motion picture photography

(Encyclopedia)motion picture photography or cinematography, photographic arts and techniques involved in making motion pictures. See also photography, still. Cinematography developed as a separate craft ve...

Rwanda

(Encyclopedia)CE5 Rwanda ro͝oänˈdä [key], officially Republic of Rwanda, republic (2015 est. pop. 11,630,000), 10,169 sq mi (26,338 sq km), E central Africa. It borders on Congo (Kinshasa) in the west, on Ug...

forestry

(Encyclopedia)forestry, the management of forest lands for wood, water, wildlife, forage, and recreation. Because the major economic importance of the forest lies in wood and wood products, forestry has been chiefl...

fortification

(Encyclopedia)fortification, system of defense structures for protection from enemy attacks. Fortification developed along two general lines: permanent sites built in peacetime, and emplacements and obstacles hasti...

pacifism

(Encyclopedia)pacifism, advocacy of opposition to war through individual or collective action against militarism. Although complete, enduring peace is the goal of all pacifism, the methods of achieving it differ. S...

organized crime

(Encyclopedia)organized crime, criminal activities organized and coordinated on a national scale, often with international connections. The American tradition of daring desperadoes like Jesse James and John Dilling...

pollution

(Encyclopedia)pollution, contamination of the environment as a result of human activities. The term pollution refers primarily to the fouling of air, water, and land by wastes (see air pollution; water pollution; s...