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hydrogen peroxide

(Encyclopedia)hydrogen peroxide, chemical compound, H2O2, a colorless, syrupy liquid that is a strong oxidizing agent and, in water solution, a weak acid. It is miscible with cold water and is soluble in alcohol an...

Stephenson, George

(Encyclopedia)Stephenson, George, 1781–1848, British engineer, noted as a locomotive builder. He learned to read and write in night school at the age of 18, while working in a colliery. He constructed (1814) a tr...

air forces

(Encyclopedia)air forces, those portions of a nation's military organization employing heavier-than-air aircraft for reconnaissance, support of ground troops, aerial combat, and bombing of enemy lines of communicat...

Uist, North, and South Uist

(Encyclopedia)Uist, North yo͞oˈĭst, o͞oˈ– [key], and South Uist, islands, two of the Outer Hebrides, Western Isles council area, NW Scotland. North Uist (1985 est. pop. 3,300), is 18 mi (29 km) long and 13 m...

Ch'in, dynasty of China (221–206 b.c.)

(Encyclopedia)Ch'in chĭn [key], dynasty of China, which ruled from 221 b.c. to 206 b.c. The word China is derived from Ch'in, the first dynasty to unify the country by conquering the warring feudal states of the l...

Old Man of the Mountain, in Islamic history

(Encyclopedia)Old Man of the Mountain, in Islamic history: see Assassin. ...

eider, in zoology

(Encyclopedia)eider: see duck.

diet, in nutrition

(Encyclopedia)diet, food and drink regularly consumed for nourishment. Nutritionists generally recommend eating a wide variety of foods; however, some groups of people survive on a very limited diet. The traditiona...

dike, in technology

(Encyclopedia)dike, in technology: see levee.

dimension, in mathematics

(Encyclopedia)dimension, in mathematics, number of parameters or coordinates required locally to describe points in a mathematical object (usually geometric in character). For example, the space we inhabit is three...