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internal-combustion engine

(Encyclopedia)CE5 Internal-combustion engines: In the four-stroke reciprocating engine (above), a mixture of fuel and air is taken into the chamber on the down-stroke of the piston, is compressed on the up-strok...

York, Richard, duke of

(Encyclopedia)York, Richard, duke of, 1411–60, English nobleman, claimant to the throne. He was descended from Edward III through his father, Richard, earl of Cambridge, grandson of that king, and also through hi...

dictator

(Encyclopedia)dictator, originally a Roman magistrate appointed to rule the state in times of emergency; in modern usage, an absolutist or autocratic ruler who assumes extraconstitutional powers. From 501 b.c. unti...

thyristor

(Encyclopedia)thyristor, semiconductor switch used chiefly in power-control applications. Also called a silicon-controlled rectifier (SCR; see rectifier), it is a variation of the transistor. A thyristor is capable...

Grotius, Hugo

(Encyclopedia)Grotius, Hugo grōˈshəs [key], 1583–1645, Dutch jurist and humanist, whose Dutch name appears as Huigh de Groot. He studied at the Univ. of Leiden and became a lawyer when 15 years old. In Dutch p...

Assassin

(Encyclopedia)Assassin əsăsˈĭn [key], European name for the member of a secret order of the Ismaili sect of Islam. They are known as Nizaris after Nizar ibn al-Mustansir, whom they supported as caliph; the Euro...

Mount Wilson Observatory

(Encyclopedia)Mount Wilson Observatory, astronomical observatory located in California on Mt. Wilson, near Pasadena. Mt. Wilson Observatory was founded in 1904 by George E. Hale. Its equipment includes 100-in. (2.5...

social contract

(Encyclopedia)social contract, agreement or covenant by which men are said to have abandoned the “state of nature” to form the society in which they now live. The theory of such a contract, first formulated by ...

bond

(Encyclopedia)bond, in finance, usually a formal certificate of indebtedness issued in writing by governments or business corporations in return for loans. It bears interest and promises to pay a certain sum of mon...

Wright brothers

(Encyclopedia)Wright brothers, American airplane inventors and aviation pioneers. Orville Wright 1871–1948, was born in Dayton, Ohio, and Wilbur Wright, 1867–1912, near New Castle, Ind. Their interest in aviati...