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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...

Kaposi's sarcoma

(Encyclopedia)Kaposi's sarcoma käpˈəshēˌ, kəpōˈsē [key], a usually fatal cancer that was considered rare until its appearance in AIDS patients. First described by an Austro-Hungarian physician, Moritz Kapo...

Archaebacteria

(Encyclopedia)Archaebacteria ärˌkēbăktĭrˈēə [key], diverse group of bacteria (prokaryotes), sometimes called the archaea and considered a major group unto themselves. Archaebacteria are contrasted with the ...

antifreeze

(Encyclopedia)antifreeze, substance added to a solvent to lower its freezing point. The solution formed is called an antifreeze mixture. Antifreeze is typically added to water in the cooling system of an internal-c...

thermionic emission

(Encyclopedia)thermionic emission thûrmˌīŏnˈĭk [key], emission of electrons or ions by substances that are highly heated, the charged particles being called thermions. The number of thermions emitted increase...

ultrasound

(Encyclopedia)ultrasound or sonography, in medicine, technique that uses sound waves to study and treat hard-to-reach body areas. In scanning with ultrasound, high-frequency sound waves are transmitted to the area ...

brass

(Encyclopedia)brass, alloy having copper (55%–90%) and zinc (10%–45%) as its essential components. The properties of brass vary with the proportion of copper and zinc and with the addition of small amounts of o...

batholith

(Encyclopedia)batholith, enormous mass of intrusive igneous rock, that is, rock made of once-molten material that has solidified below the earth's surface (see rock). Batholiths usually are granitic (see granite) i...

Stegosaurus

(Encyclopedia)Stegosaurus stĕgəsôrˈəs [key] [Gr.,=roof lizard], quadriped ornithischian dinosaur of the late Jurassic period. About 29 ft 6 in (9 m) long, it had short forelegs, four long bony spikes on a flex...

zebu

(Encyclopedia)zebu zēˈbyo͞o [key], domestic animal of the cattle family, Bos indicus, found in parts of E Asia, India, and Africa. The zebu characteristically has a large fatty hump (sometimes two humps) over th...