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nucleus, in physics

(Encyclopedia)nucleus, in physics, the extremely dense central core of an atom. Following the discovery of radioactivity by A. H. Becquerel in 1896, Ernest Rutherford identified two types of radiation given off b...

drainage, in mining

(Encyclopedia)drainage, in mining, removal of water seeping into shafts and other underground mine workings from the surrounding ground. Unless seeping water is removed continually, it may endanger haulage and mini...

drum, in music

(Encyclopedia)CE5 Drums drum, in music, percussion instrument, known in various forms and played throughout the world and throughout history. Essentially a drum is a frame over which one or more membranes or sk...

division, in mathematics

(Encyclopedia)division, fundamental operation in arithmetic; the inverse of multiplication. Division may be indicated by the symbol ÷, as in 15 ÷ 3, or simply by a fraction, 15/3. The number that is being divided...

spring, in geology

(Encyclopedia)spring, in geology, natural flow of water from the ground or from rocks, representing an outlet for the water that has accumulated in permeable rock strata underground. Some of the water that falls as...

brake, in technology

(Encyclopedia)CE5 Shoe brake CE5 Disk brake brake, in technology, device to slow or stop the motion of a mechanism or vehicle. The vacuum brake system, or vacuum brake, depends upon the use of a vacuum to ...

set, in mathematics

(Encyclopedia)CE5 Union and intersection of sets A and B: The union of A and B, A∪B, contains all members belonging to either A or B. The intersection of A and B, A∩B, contains all members common to both A a...

hyacinth, in botany

(Encyclopedia)hyacinth, any plant of the genus Hyacinthus, bulbous herbs of the family Liliaceae (lily family) native to the Mediterranean region and South Africa. The common, or Dutch, hyacinth of house and garden...

seal, in zoology

(Encyclopedia)seal, carnivorous aquatic mammal with front and hind feet modified as flippers, or fin-feet. The name seal is sometimes applied broadly to any of the fin-footed mammals, or pinnipeds, including the wa...

mode, in statistics

(Encyclopedia)mode, in statistics, an infrequently used type of average. In a group of numbers the mode is the number occurring most frequently. In the group 1, 4, 5, 5, 6, 6, 6, 6, 9, 9, the mode is 6 because it o...