Columbia Encyclopedia

(Encyclopedia) ring, in mathematics, system consisting of a set R of elements and two binary operations, such that addition makes R a commutative group and multiplication is associative and distributes over addition...

(Encyclopedia) Ring des Nibelungen, Der: see Nibelungen. ...

(Encyclopedia) Kaufman, George S. kôfˈmən [key], 1889–1961, American dramatist and journalist, b. Pittsburgh as George Kaufman. As a drama critic for various New York newspapers he was influential in raising th...

(Encyclopedia) aromatic compound, any of a large class of compounds that includes benzene and compounds that resemble benzene in certain of their chemical properties. Originally applied to a small class of pleasant-...

(Encyclopedia) cyclopropane, C3H6, a gaseous hydrocarbon. It is a cyclic alkane, its three carbon atoms being joined together in a ring. The angle between successive carbon-carbon bonds in the ring is only 60°, muc...

(Encyclopedia) Challenger, U.S. space shuttle. It exploded (Jan. 28, 1986) 73 seconds into its tenth flight, killing all seven crew members, including the first civilian in space, schoolteacher Christa McAuliffe. Th...

(Encyclopedia) cyclic compound, any one of a class of compounds whose molecules contain a number of atoms bonded together to form a closed chain or ring. If all of the atoms that form the ring are carbon, the compou...

(Encyclopedia) Pacquiao, Manny (Emmanuel Dapidran Pacquiao), 1978–, Phillipine boxer and politician, b. Mindanao. From his first professional win at age 16 he has gone on to win world titles in eight different wei...

(Encyclopedia) Atlas, in astronomy, one of the named moons, or natural satellites, of Saturn. Also known as Saturn XV (or S15), Atlas is a small, irregularly shaped (nonspherical) body measuring about 25 mi (40 km) ...

(Encyclopedia) Stevenson, Teófilo, 1952–2012, Cuban heavyweight boxer, b. Puerto Padre. One of the greatest amateur boxers ever to enter the ring, he won gold medals at the Munich (1972), Montreal (1976), and Mos...