Columbia Encyclopedia

Search results

500 results found

norepinephrine

(Encyclopedia)norepinephrine nôrˌĕpīnĕfˈrən [key], a neurotransmitter in the catecholamine family that mediates chemical communication in the sympathetic nervous system, a branch of the autonomic nervous sys...

Wang Mang

(Encyclopedia)Wang Mang wäng mäng [key], 45 b.c.–a.d. 23, Chinese Han dynasty regent who usurped the throne and ruled (a.d. 8–23) as emperor of the Hsin [new] court, carrying out many reforms. Although he por...

adhesive

(Encyclopedia)adhesive, substance capable of sticking to surfaces of other substances and bonding them to one another. The term adhesive cement is sometimes used in place of adhesive, especially when referring to a...

Bassiouni, M. Cherif

(Encyclopedia)Bassiouni, M. Cherif (Mahmoud Cherif Bassiouni), 1937–2017, Egyptian-American international criminal law jurist and human-rights advocate, b. Cairo. Bassiouni fought for Egypt in the Suez conflict (...

spark chamber

(Encyclopedia)spark chamber, in physics, device for recording the passage of elementary particles produced by reactions in a particle accelerator. Particles pass through a stack of metal plates or wire grids that a...

caffeine

(Encyclopedia)caffeine kăfēnˈ [key], odorless, slightly bitter alkaloid found in coffee, tea, kola nuts (see cola), ilex plants (the source of the Latin American drink maté), and, in small amounts, in cocoa (se...

vibration

(Encyclopedia)vibration, in physics, commonly an oscillatory motion—a movement first in one direction and then back again in the opposite direction. It is exhibited, for example, by a swinging pendulum, by the pr...

liquid

(Encyclopedia)liquid, one of the three commonly recognized states in which matter occurs, i.e., that state, as distinguished from solid and gas, in which a substance has a definite volume but no definite shape. T...

dam

(Encyclopedia)dam, barrier, commonly across a watercourse, to hold back water, often forming a reservoir or lake; dams are also sometimes used to control or contain rockslides, mudflows, and the like in regions whe...

El Niño–Southern Oscillation

(Encyclopedia)El Niño–Southern Oscillation (ENSO) ĕl nēnˈyō [key], large-scale climatic fluctuation of the tropical Pacific Ocean and the overlying atmosphere. The El Niño [Span.,=the child] is the South Am...