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period, in geologic time

(Encyclopedia)period, unit of time on the geologic timescale. Periods are shorter than an era and longer than an epoch. Periods are of variable length, generally lasting tens of millions of years, with characterist...

electromagnet

(Encyclopedia)CE5 Electromagnet electromagnet, device in which magnetism is produced by an electric current. Any electric current produces a magnetic field, but the field near an ordinary straight conductor is ...

image

(Encyclopedia)image, in optics, likeness or counterpart of an object produced when rays of light coming from that object are reflected from a mirror or are refracted by a lens. An image of an object is also formed ...

Miranda v. Arizona

(Encyclopedia)Miranda v. Arizona, U.S. Supreme Court case (1966) in the area of due process of law (see Fourteenth Amendment). The decision reversed an Arizona court's conviction of Ernesto Miranda on kidnapping an...

kinetic-molecular theory of gases

(Encyclopedia)kinetic-molecular theory of gases, physical theory that explains the behavior of gases on the basis of the following assumptions: (1) Any gas is composed of a very large number of very tiny particles ...

belligerency

(Encyclopedia)belligerency bəlĭjˈərənsē [key], in international law, status of parties legally at war. Belligerency exists in a war between nations or in a civil war if the established government treats the i...

Addison, Joseph

(Encyclopedia)Addison, Joseph, 1672–1719, English essayist, poet, and statesman. He was educated at Charterhouse, where he was a classmate of Richard Steele, and at Oxford, where he became a distinguished classic...

Pyongyang

(Encyclopedia)Pyongyang pēyŭngˈyängˈ [key], Chin. Pingyang, Jap. Heijo, city (1993 pop. 2,741,260), capital of North Korea, SW North Korea, on a high bluff above the Taedong River. It is a special city with th...

Roe v. Wade

(Encyclopedia)Roe v. Wade, case decided in 1973 by the U.S. Supreme Court. Along with Doe v. Bolton, this decision legalized abortion in the first trimester of ...

protocol

(Encyclopedia)protocol prōˈtəkŏl [key], term referring to rules governing diplomatic conduct or to a variety of written instruments. Examples of the latter are authenticated minutes of international conferences...