Columbia Encyclopedia

Search results

500 results found

touch

(Encyclopedia)touch, tactile sensation received by the skin, enabling the organism to detect objects or substances in contact with the body. End organs (nerve endings) in the skin convey the impression to the brain...

tourniquet

(Encyclopedia)tourniquet to͝orˈnĭkĕt, –kā, tûrˈ– [key], compression device used to cut off the flow of blood to a part of the body, most often an arm or leg. It may be a special surgical instrument, a ru...

oxyacetylene torch

(Encyclopedia)oxyacetylene torch ŏkˌsēəsĕtˈəlēn [key], tool that mixes and burns oxygen and acetylene to produce an extremely hot flame. This torch can be used for cutting steel and for welding iron and var...

celibacy

(Encyclopedia)celibacy sĕlˈĭbəsē [key], voluntary refusal to enter the married state, with abstinence from sexual activity. It is one of the typically Christian forms of asceticism. In ancient Rome the vestal ...

brown dwarf

(Encyclopedia)brown dwarf, in astronomy, celestial body that is larger than a planet but does not have sufficient mass to convert hydrogen into helium via nuclear fusion as stars do. Also called “failed stars,”...

blizzard

(Encyclopedia)blizzard, winter storm characterized by high winds, low temperatures, and driving snow; according to the official definition given in 1958 by the U.S. Weather Bureau, the winds must exceed 35 mi (56 k...

echo, in acoustics

(Encyclopedia)echo, reflection of a sound wave back to its source in sufficient strength and with a sufficient time lag to be separately distinguished. If a sound wave returns within 1⁄10 sec, the human ear is in...

Gulf Stream

(Encyclopedia)Gulf Stream, warm ocean current of the N Atlantic Ocean, off E North America. It was first described (1513) by Spanish explorer Ponce de León. The Gulf Stream originates in the Gulf of Mexico and, as...

phosphorescence

(Encyclopedia)phosphorescence fŏsˌfərĕsˈəns [key], luminescence produced by certain substances after absorbing radiant energy or other types of energy. Phosphorescence is distinguished from fluorescence in th...

Brownian movement

(Encyclopedia)Brownian movement or motion, zigzag, irregular motion exhibited by minute particles of matter when suspended in a fluid. The effect has been observed in all types of colloidal suspensions (see colloid...