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lens, in optics

(Encyclopedia)CE5 Lenses lens, device for forming an image of an object by the refraction of light. In its simplest form it is a disk of transparent substance, commonly glass, with its two surfaces curved or wi...

glass

(Encyclopedia)glass, hard substance, usually brittle and transparent, composed chiefly of silicates and an alkali fused at high temperature. Glass has become invaluable in modern architecture, illumination, elect...

art conservation and restoration

(Encyclopedia)art conservation and restoration, the preservation of structurally sound works of art, the halting of processes that lead to the damage of works of art, and the repair of already damaged works of art....

Alexander the Great

(Encyclopedia)CE5 Empire of Alexander the Great (including dependencies) Alexander the Great or Alexander III, 356–323 b.c., king of Macedon, conqueror of much of Asia. Whether or not Alexander had plans fo...

iron

(Encyclopedia)iron, metallic chemical element; symbol Fe [Lat. ferrum]; at. no. 26; at. wt. 55.845; m.p. about 1,535℃; b.p. about 2,750℃; sp. gr. 7.87 at 20℃; valence +2, +3, +4, or +6. Iron is biologically s...

pottery

(Encyclopedia)pottery, the baked-clay wares of the entire ceramics field. For a description of the nature of the material, see clay. American art pottery flourished in the first half of the 20th cent., with wor...

Marxism

(Encyclopedia)Marxism, economic and political philosophy named for Karl Marx. It is also known as scientific (as opposed to utopian) socialism. Marxism has had a profound impact on contemporary culture; modern comm...

Supreme Court, United States

(Encyclopedia)CE5 Supreme Court, United States, highest court of the United States, established by Article 3 of the Constitution of the United States. With the emergence of a working conservative majority,...

Paraguay, country, South America

(Encyclopedia)CE5 Paraguay pârˈəgwā, –gwī, Span. pärägwīˈ [key], officially Republic of Paraguay, republic (2015 est. pop. 6,639,000), 157,047 sq mi (406,752 sq km), S central South America. Paraguay ...

cancer, in medicine

(Encyclopedia)cancer, in medicine, common term for neoplasms, or tumors, that are malignant. Like benign tumors, malignant tumors do not respond to body mechanisms that limit cell growth. Unlike benign tumors, mali...

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