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stun gun

(Encyclopedia)stun gun, hand-held electronic device that produces a high-voltage pulse that can immobilize a person for several minutes with no permanent damage in most cases. It is powered by ordinary batteries, w...

thresher shark

(Encyclopedia)thresher shark, long-tailed, warm-water shark, genus Alopias. The upper fork of its tail is slender and sickle-shaped and is about equal in length to the rest of the body. This shark uses its tail str...

astigmatism

(Encyclopedia)astigmatism əstĭgˈmətĭzˌəm [key], type of faulty vision caused by a nonuniform curvature in the refractive surfaces—usually the cornea, less frequently the lens—of the eye. As a result, lig...

ohmmeter

(Encyclopedia)ohmmeter ōmˈmēˌtər [key], instrument used to measure the electrical resistance of a conductor. It is usually included in a single package with a voltmeter, and often an ammeter. In normal usage, ...

nail, in anatomy

(Encyclopedia)nail, in anatomy, the horny outgrowth shielding the tip of the finger and the toe in humans and most other primates. The nail consists of dead cells pushed outward by dividing cells in the root, a fol...

Augustine of Canterbury, Saint

(Encyclopedia)Augustine of Canterbury, Saint ôˈgəstēn, –tĭn; ôgŭsˈtĭn [key], d. c.605, Italian missionary, called the Apostle of the English, first archbishop of Canterbury (from 601). A Roman monk, he w...

psoriasis

(Encyclopedia)psoriasis sôrīˈəsĭs [key], occasionally acute but usually chronic and recurrent inflammation of the skin. The exact cause is unknown, but the disease appears to be an inherited, possibly autoimmu...

pasture

(Encyclopedia)pasture, land used for grazing livestock. Land unsuited for cultivation, e.g., hilly or stony land, may be used as pasture. Tilled land and meadow may be pastured after the crops are removed. Pastures...

imprinting

(Encyclopedia)imprinting, acquisition of behavior in many animal species, in which, at a critical period early in life, the animals form strong and lasting attachments. Imprinting is important for normal social dev...

Hart, Oliver Simon D'Arcy

(Encyclopedia)Hart, Oliver Simon D'Arcy, 1948–, British-American economist, b. London, England, Ph.D. Princeton, 1974. He has been a professor at the London School of Economics (1981–85), the Massachusetts Inst...