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number

(Encyclopedia)number, entity describing the magnitude or position of a mathematical object or extensions of these concepts. A real or complex number z is called algebraic if it is the root of a polynomial equati...

mass transit

(Encyclopedia)mass transit, public transportation systems designed to move large numbers of passengers. The history of mass transportation is intimately connected to industrialization, urbanization, and the sepa...

motion

(Encyclopedia)motion, the change of position of one body with respect to another. The rate of change is the speed of the body. If the direction of motion is also given, then the velocity of the body is determined; ...

Restoration, in English history

(Encyclopedia)Restoration, in English history, the reestablishment of the monarchy on the accession (1660) of Charles II after the collapse of the Commonwealth (see under commonwealth) and the Protectorate. The ter...

wave, in physics

(Encyclopedia)wave, in physics, the transfer of energy by the regular vibration, or oscillatory motion, either of some material medium or by the variation in magnitude of the field vectors of an electromagnetic fie...

shark

(Encyclopedia)shark, member of a group of almost exclusively marine and predaceous fishes. There are about 250 species of sharks, ranging from the 2-ft (60-cm) pygmy shark to 50-ft (15-m) giants. They are found in ...

Johnson, Andrew

(Encyclopedia)Johnson, Andrew, 1808–75, 17th President of the United States (1865–69), b. Raleigh, N.C. On Apr. 15, 1865, following Lincoln's assassination, Johnson took the oath of office as President. His...

Wordsworth, William

(Encyclopedia)Wordsworth, William, 1770–1850, English poet, b. Cockermouth, Cumberland. One of the great English poets, he was a leader of the romantic movement in England. Wordsworth's personality and poetry ...

Solzhenitsyn, Aleksandr Isayevich

(Encyclopedia)Solzhenitsyn, Aleksandr Isayevich əlyĭksänˈdər ēsīˈəvĭch sôlˌzhənētˈsĭn [key], 1918–2008, Russian writer widely regarded as one of the greatest and most influential authors of the 20...

migration of animals

(Encyclopedia)migration of animals, movements of animals in large numbers from one place to another. In modern usage the term is usually restricted to regular, periodic movements of populations away from and back t...