Columbia Encyclopedia

(Encyclopedia) piano or pianoforte, musical instrument whose sound is produced by vibrating strings struck by felt hammers that are controlled from a keyboard. The piano's earliest predecessor was the dulcimer. The ...

(Encyclopedia) diffusion, in chemistry, the spontaneous migration of substances from regions where their concentration is high to regions where their concentration is low. Diffusion is important in many life process...

(Encyclopedia) Boston, city (2020 pop. 692,600), state capital and seat of Suffolk co., E Mass., on Boston Bay, an arm of Massachusetts Bay; inc. 1822. The city includ...

(Encyclopedia) Ai Weiwei īˈ wāwā [key], 1957–, Chinese artist, architect, filmmaker, and political activist. He is the son of poet Ai Ch'ing, who was internally exiled (1958–76) to work camps with his family...

(Encyclopedia) Lisbon lĭzˈbən [key], Port. Lisboa, ancient Olisipo, city (1991 pop. 677,790), W Portugal, capital of Portugal and of Lisboa dist., on the Tagus River where it broadens to enter the Atlantic Ocean....

(Encyclopedia) Hagia Sophia häˈjə sōfēˈə, hāˈjēə, [key] [Gr.,=Holy Wisdom] or Santa Sophia, Turkish Ayasofya, originally a Christian church at Constantinople (now İstanbul, Turkey) and then a mosque unde...

(Encyclopedia) New Orleans ôrˈlēənz –lənz, ôrlēnzˈ [key], city (2006 pop. 187,525), coextensive with Orleans parish, SE La., between the Mississippi River and Lake Pontchartrain, 107 mi (172 km) by water f...

(Encyclopedia)  CE5 Hong Kong hŏng kŏng [key], Mandarin Xianggang, special administrative region of China, formerly a British crown colony (2015 est. pop. 7,246,000), land area 422 sq mi (1,092 sq km), adjacent ...

(Encyclopedia) land use, exploitation of land for agricultural, industrial, residential, recreational, or other purposes. Because the United States historically has a laissez-faire attitude toward land use, the land...

(Encyclopedia) castle, type of fortified dwelling characteristic of the Middle Ages. Fortification of towns had been in practice since antiquity, but in the 9th cent. feudal lords began to develop the private fortre...