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arc, in electricity

(Encyclopedia)arc, in electricity, highly luminous and intensely hot discharge of electricity between two electrodes. The arc was discovered early in the 19th cent. by the English scientist Sir Humphry Davy, who so...

arc, in geometry

(Encyclopedia)arc, in geometry, a curved line or any part of it; in particular, a portion of the circumference of a circle. The length s of an arc of a circle of radius r and subtending a central angle of θ radian...

Larissa, in astronomy

(Encyclopedia)Larissa, in astronomy, one of the natural satellites, or moons, of Neptune. ...

larva, in zoology

(Encyclopedia)larva, independent, immature animal that undergoes a profound change, or metamorphosis, to assume the typical adult form. Larvae occur in almost all of the animal phyla; because most are tiny or micro...

key, in music

(Encyclopedia)key. 1 In music, term used to indicate the scale from which the tonal material of a given composition is derived. To say, for example, that a composition is in the key of C major means that it uses as...

archangel, in religion

(Encyclopedia)archangel ärkˈānjəl [key], chief angel. They are four to seven in number. Sometimes specific functions are ascribed to them. The four best known in Christian tradition are Michael, Gabriel, Raphae...

lens, in optics

(Encyclopedia)CE5 Lenses lens, device for forming an image of an object by the refraction of light. In its simplest form it is a disk of transparent substance, commonly glass, with its two surfaces curved or wi...

Leo, in astronomy

(Encyclopedia)Leo [Lat.,=the lion], northern constellation lying S of Ursa Major and on the ecliptic (apparent path of the sun through the heavens) between Cancer and Virgo; it is one of the constellations of the z...

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