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angelfish
(Encyclopedia)angelfish, common name for certain members of the Pomacanthidae, a family of brightly colored reef-dwelling tropical fishes with compressed bodies and small mouths and teeth. They were formerly classi...homelessness
(Encyclopedia)homelessness, the condition of not having a permanent place to live, widely perceived as a societal problem only beginning in the 1980s. Figures for the number of homeless people in the United States ...luminism
(Encyclopedia)luminism lo͞oˈmĭnĭzˌəm [key], American art movement of the 19th cent. Luminism was an outgrowth of the Hudson River school. In its concern for capturing the effects of light and atmosphere it is...harrow, in agriculture
(Encyclopedia)harrow, farm implement, consisting of a wooden or metal framework bearing metal disks, teeth, or sharp projecting points, called tines, which is dragged over plowed land to pulverize the clods of eart...Ainu
(Encyclopedia)Ainu īˈno͞o [key], aborigines of Japan who may be descended from a Caucasoid people who once lived in N Asia. More powerful invaders from the Asian mainland gradually forced the Ainu to retreat to ...Sagan, Carl Edward
(Encyclopedia)Sagan, Carl Edward sāˈgən [key], 1934–96, American astronomer and popularizer of science, b. New York City. Early in his career he investigated radio emissions from Venus and concluded that the c...spore
(Encyclopedia)spore, term applied both to a resistant or resting stage occurring among various unicellular organisms (especially bacteria) and to an asexual reproductive cell produced by many unicellular plants and...silica
(Encyclopedia)silica or silicon dioxide, chemical compound, SiO2. It is insoluble in water, slightly soluble in alkalies, and soluble in dilute hydrofluoric acid. Pure silica is colorless to white. It occurs in sev...seeing
(Encyclopedia)seeing, in astronomy, the clarity with which stars and other celestial objects can be observed. It is primarily determined by the atmosphere of the earth. The most obvious phenomenon is twinkling, whe...tar and pitch
(Encyclopedia)tar and pitch, viscous, dark-brown to black substances obtained by the destructive distillation of coal, wood, petroleum, peat, and certain other organic materials. The heating or partial burning of w...Browse by Subject
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