Columbia Encyclopedia

(Encyclopedia) birth control, practice of contraception for the purpose of limiting reproduction. Although contraceptive techniques had been known in ancient Egypt, Greece, and Rome, the modern movement for birth ...

(Encyclopedia) Obama, Barack (Barack Hussein Obama 2d), bəräkˈ ho͞osānˈ ōbäˈmə [key], 1961–, 44th president of the United States (2009–17), b. Honolulu, grad. Columbia (B.A. 1983), Harvard Law School ...

(Encyclopedia) fascism făshˈĭzəm [key], totalitarian philosophy of government that glorifies the state and nation and assigns to the state control over every aspect of national life. The name was first used by t...

(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)  CE5 Bohr-Rutherford atom CE5 Probability distribution of the electron in the hydrogen atom: A. Ground state B. Highly excited state atom [Gr.,=uncuttable (indivisible)], basic unit of matte...

(Encyclopedia) air pollution, contamination of the air by noxious gases and minute particles of solid and liquid matter (particulates) in concentrations that endanger health. The major sources of air pollution are t...

(Encyclopedia) Roosevelt, Theodore, 1858–1919, 26th President of the United States (1901–9), b. New York City. Alice, his daughter by his first wife, married Nicholas Longworth in the White House; “Princ...

(Encyclopedia)  CE5 Electrical and radio symbols electricity, class of phenomena arising from the existence of charge. The basic unit of charge is that on the proton or electron—the proton's charge is designate...

(Encyclopedia) periodical, a publication that is issued regularly. It is distinguished from the newspaper in format in that its pages are smaller and are usually bound, and it is published at weekly, monthly, quarte...

(Encyclopedia) Jefferson, Thomas, 1743–1826, 3d President of the United States (1801–9), author of the Declaration of Independence, and apostle of agrarian democracy. After 1809, Jefferson lived in retirem...