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zero

(Encyclopedia)zero, that number which, when added to any number, leaves the latter unchanged; its symbol is 0. The introduction of zero into the decimal system was the most significant achievement in the developmen...

biology

(Encyclopedia)biology, the science that deals with living things. It is broadly divided into zoology, the study of animal life, and botany, the study of plant life. Subdivisions of each of these sciences include cy...

carbonated beverage

(Encyclopedia)carbonated beverage, an effervescent drink that releases carbon dioxide under conditions of normal atmospheric pressure. Carbonation may occur naturally in spring water that has absorbed carbon dioxid...

carbonyl group

(Encyclopedia)carbonyl group kärˈbənĭl [key], in chemistry, functional group that consists of an oxygen atom joined by a double bond to a carbon atom. The carbon atom is joined to the remainder of the molecule ...

Weizmann, Chaim

(Encyclopedia)Weizmann, Chaim khīmˈ vītsˈmän [key], 1874–1952, scientist and Zionist leader, first president (1948–52) of Israel, b. Russia, grad. Univ. of Freiburg, 1899. He lectured in chemistry at the U...

erosion

(Encyclopedia)erosion ĭrōˈzhən [key], general term for the processes by which the surface of the earth is constantly being worn away. The principal agents are gravity, running water, near-shore waves, ice (most...

APRA

(Encyclopedia)APRA äˈprä [key] or the Alianza Popular Revolucionaria Americana, reformist political party in Peru, also called the Partido Aprista. Founded (1924) by Victor Raúl Haya de la Torre while in exile,...

pendulum

(Encyclopedia)pendulum, a mass, called a bob, suspended from a fixed point so that it can swing in an arc determined by its momentum and the force of gravity. The length of a pendulum is the distance from the point...

Pusey, Edward Bouverie

(Encyclopedia)Pusey, Edward Bouverie pyo͞oˈzē [key], 1800–1882, English clergyman, leader in the Oxford movement. Having studied at Christ Church College, Oxford, Pusey was elected a fellow of Oriel College (1...

hassium

(Encyclopedia)hassium hăsˈēəm, häsˈ– [key], artificially produced radioactive chemical element; symbol Hs; at. no. 108; mass number of most stable isotope 277; m.p., b.p., sp. gr., and valence unknown. Situ...