Columbia Encyclopedia

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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...

Columbia, U.S. space shuttle

(Encyclopedia)Columbia, U.S. space shuttle. On its 28th flight, on Feb. 1, 2003, after completing a 16-day scientific mission, the spacecraft disintegrated during reentry, killing its seven-person crew. About 16 mi...

calcium oxide

(Encyclopedia)calcium oxide, chemical compound, CaO, a colorless, cubic crystalline or white amorphous substance. It is also called lime, quicklime, or caustic lime, but commercial lime often contains impurities, e...

sweetener, artificial

(Encyclopedia)sweetener, artificial, substance used as a low-calorie sugar substitute. Saccharin, cyclamates, and aspartame have been the most commonly used artificial sweeteners. Saccharin, a coal-tar derivative t...

bee fly

(Encyclopedia)bee fly, name for the small- to medium-sized flies of the family Bombyliidae, many of which resemble bees in appearance and behavior. This mimicry provides bee flies with some measure of protection ag...

tempering

(Encyclopedia)tempering, process involving slow and moderate heating to increase the hardness and toughness of metals that have undergone previous heat treatment. Metals are usually hardened (see hardening) by bein...

San Salvador, city, El Salvador

(Encyclopedia)San Salvador sän sälväᵺōrˈ [key], city (1993 pop. 402,448), central El Salvador, capital and largest city of the country. It is the center of El Salvador's trade and communications. Beer, tobac...

resistance, in electricity

(Encyclopedia)resistance, property of an electric conductor by which it opposes a flow of electricity and dissipates electrical energy away from the circuit, usually as heat. Optimum resistance is provided by a con...

permafrost

(Encyclopedia)permafrost, permanently frozen soil, subsoil, or other deposit, characteristic of arctic and some subarctic regions; similar conditions are also found at very high altitudes in mountain ranges. In 196...