Also found in: Dictionary, Thesaurus, Medical, Wikipedia.
atomic bomb, atom bomb
a bomb with a nuclear charge dropped from aircraft. The first atom bombs were made in the USA at the end of World War II. The explosion of an atom bomb releases a tremendous amount of nuclear energy. In July 1945 the Americans tested the atom bomb and then dropped two bombs with the equivalent of 20,000 tons of TNT on the Japanese cities of Hiroshima (Aug. 6) and Nagasaki (Aug. 9, 1945). The explosion of the atom bombs caused great destruction in these cities and enormous casualties among the peaceful civilian population. More than 140,000 people were killed or wounded in Hiroshima and about 75,000 in Nagasaki. Subsequently several hundred thousand people died as a result of the aftereffects of the atomic bombardment. The use of the atom bombs was not caused by any military necessity. The American ruling circles gambled on a temporary US monopoly in nuclear weaponry and tried to use it to intimidate freedom-loving peoples. But the atomic “secrets” were discovered as early as 1947 by Soviet scientists headed by Academician I. V. Kurchatov; in August 1949 the USSR made an experimental explosion of an atomic device, which led to the end of any possibility of atomic blackmail. The term “atom bomb” is now rarely used.