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rain

(Encyclopedia)rain, precipitation in liquid form. It consists of drops of water falling from clouds; if the drops are very small, they are collectively termed drizzle. Rain plays a key role in the hydrologic, or wa...

mass extinction

(Encyclopedia)mass extinction, the extinction of a large percentage of the earth's species, opening ecological niches for other species to fill. There have been at least ten such events. The five greatest were thos...

diamond

(Encyclopedia)diamond, mineral, one of two crystalline forms of the element carbon (see allotropy), the hardest natural substance known, used as a gem and in industry. The discoveries of 1870–71 in South Africa...

Chinese

(Encyclopedia)Chinese, subfamily of the Sino-Tibetan family of languages (see Sino-Tibetan languages), which is also sometimes grouped with the Tai, or Thai, languages in a Sinitic subfamily of the Sino-Tibetan lan...

John, king of England

(Encyclopedia)John, 1167–1216, king of England (1199–1216), son of Henry II and Eleanor of Aquitaine. John, though often cruel and treacherous, was an excellent administrator, much concerned with rendering...

mining

(Encyclopedia)mining, extraction of solid mineral resources from the earth. These resources include ores, which contain commercially valuable amounts of metals, such as iron and aluminum; precious stones, such as d...

agrarian reform

(Encyclopedia)agrarian reform, redistribution of the agricultural resources of a country. Traditionally, agrarian, or land, reform is confined to the redistribution of land; in a broader sense it includes related c...

sound

(Encyclopedia)CE5 Sound waves: An air pressure wave radiating outward from a loudspeaker is perceived as sound. sound, any disturbance that travels through an elastic medium such as air, ground, or water to be ...

smoking

(Encyclopedia)smoking, inhalation and exhalation of the fumes of burning tobacco in cigars and cigarettes and pipes; in the 21st cent., vaping, the similar use of e-cigarettes, also has become common. Some persons ...

migration

(Encyclopedia)migration, of people, geographical movements of individuals or groups for the purpose of permanently resettling. Normal internal migration has been characterized by a population shift from rural t...