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Azerbaijan, region, Iran

(Encyclopedia)Azerbaijan äˌzĕrbījänˈ, ăˌzər– [key], Iran. Azarbayejan, region, c.34,280 sq mi (88,785 sq km), NW Iran, divided into the provinces of East Azerbaijan, ...

sunspots

(Encyclopedia)sunspots, dark, usually irregularly shaped spots on the sun's surface that are actually solar magnetic storms. The spots are darker because the temperature of the spots is lower than that of the surro...

Miami, cities, United States

(Encyclopedia)Miami mīămˈē, –ə [key]. 1 City (1990 pop. 358,548), seat of Dade co., SE Fla., on Biscayne Bay at the mouth of the Miami River; inc. 1896. The region of Greater Miami encompasses all of Dade co...

microscope

(Encyclopedia)CE5 Compound microscope microscope, optical instrument used to increase the apparent size of an object. The electron microscope, which is not limited by the powers of optical lenses and light,...

rocket, in aeronautics

(Encyclopedia)CE5 Relative positions of the components of the Saturn V rocket, the U.S. space vehicle used in the moon missions rocket, any vehicle propelled by ejection of the gases produced by combustion of s...

mine, in warfare

(Encyclopedia)mine, in warfare, term formerly applied to a system of tunnels dug under an army fortification and ending in a chamber where either explosives were placed to be detonated at a chosen moment or the sup...

helium

(Encyclopedia)helium hēˈlēəm [key], gaseous chemical element; symbol He; at. no. 2; at. wt. 4.0026; m.p. below −272℃ at 26 atmospheres pressure; b.p. −268.934℃ at 1 atmosphere pressure; density 0.1785 g...

conservation laws

(Encyclopedia)conservation laws, in physics, basic laws that together determine which processes can or cannot occur in nature; each law maintains that the total value of the quantity governed by that law, e.g., mas...

commerce, in economics

(Encyclopedia)commerce, traffic in goods, usually thought of as trade between states or nations. Engaged in by all peoples from the earliest times, it has been carried on in some areas and by some peoples more than...

Cleveland, cities, United States

(Encyclopedia)Cleveland. 1 City (2020 pop. 372,674), seat of Cuyahoga co., NE Ohio, on Lake Erie at the mouth of the Cuyahoga River; laid out (1796) by Moses ...