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cylinder

(Encyclopedia)CE5 Cylinder cylinder, in mathematics, surface generated by a line moving parallel to a given fixed line and continually intersecting a given fixed curve called the directrix; each line of the fam...

Lobachevsky, Nikolai Ivanovich

(Encyclopedia)Lobachevsky, Nikolai Ivanovich nyĭkəlīˈ ēväˈnəvĭch ləbəchĕfˈskē [key], 1793–1856, Russian mathematician. A pioneer in non-Euclidean geometry, he challenged Euclid's fifth postulate tha...

staff

(Encyclopedia)staff, in musical notation, a set of horizontal lines upon and between which notes are written so as to determine their relative pitch, and in connection with a clef, their absolute pitch. Staffs with...

Rzhev

(Encyclopedia)Rzhev ərzhĕfˈ [key], city (1989 est. pop. 70,000), NW European Russia, on the Volga River and on a major rail line to Moscow. It has textile plants and repair shops for railroad equipment. Rzhev, a...

Golden Section

(Encyclopedia)CE5 Rectangle ABCD is a golden rectangle. Removing the square AEFD leaves the rectangle EBCF Golden Section, in mathematics, division of a line segment into two segments such that the ratio of the...

Moore, John Bassett

(Encyclopedia)Moore, John Bassett, 1860–1947, American authority on international law, b. Smyrna, Del. He was admitted to the Delaware bar in 1883. He was (1885–86) a law clerk in the Dept. of State and was (18...

Elephantine

(Encyclopedia)Elephantine ĕlˌəfăntīˈnē [key], island, SE Egypt, in the Nile below the First Cataract, near Aswan. In ancient times it was a military post guarding the southern frontier of Egypt. The Elephant...

Doomsday 2000

(Encyclopedia)Doomsday 2000, term coined by Canadian computer consultant Peter de Jager in 1993 to describe the operational and financial impact of a defect of contemporary computer hardware and software, known as ...

Hywel Dda

(Encyclopedia)Hywel Dda hŭˈwəl ᵺä [key], or Howel the Good, d. 950?, king of Wales. He brought much of Wales under a single rule and is credited with the codification of Welsh laws. The earliest extant texts ...

Ghardaïa

(Encyclopedia)Ghardaïa gärdäyäˈ [key], town, N Algeria. It is the chief town of the Mzab, a stony, barren ...