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A bomb is an explosive weapon that uses the exothermic reaction of an explosive material to provide an extremely sudden and violent release of energy. Detonations inflict damage principally through ground- and atmosphere-transmitted mechanical stress, the impact and penetration of pressure-driven projectiles, pressure damage, and explosion-generated effects. Bombs have been utilized since the 11th century starting in East Asia.
The term bomb is not usually applied to explosive devices used for civilian purposes such as construction or mining, although the people using the devices may sometimes refer to them as a "bomb". The military use of the term "bomb", or more specifically aerial bomb action, typically refers to airdropped, unpowered explosive weapons most commonly used by air forces and naval aviation. Other military explosive weapons not classified as "bombs" include shells, depth charges , or land mines. In unconventional warfare, other names can refer to a range of offensive weaponry. For instance, in recent Middle Eastern conflicts, homemade bombs called "improvised explosive devices" have been employed by insurgent fighters to great effectiveness.
The word comes from the Latin bombus, which in turn comes from the Greek βόμβος , an onomatopoetic term meaning "booming", "buzzing".
Explosive bombs were used in East Asia in 1221, by a Jurchen Jin army against a Chinese Song city. Bombs built using bamboo tubes appear in the 11th century. Bombs made of cast iron shells packed with explosive gunpowder date to 13th century China. The term was coined for this bomb during a Jin dynasty naval battle of 1231 against the Mongols. The History of Jin 《金史》 states that in 1232, as the Mongol general Subutai descended on the Jin stronghold of Kaifeng, the defenders had a "thunder-crash bomb" which "consisted of gunpowder put into an iron container ... then when the fuse was lit there was a great explosion the noise whereof was like thunder, audible for more than thirty miles, and the vegetation was scorched and blasted by the heat over an area of more than half a mou. When hit, even iron armour was quite pierced through." The Song Dynasty official Li Zengbo wrote in 1257 that arsenals should have several hundred thousand iron bomb shells available and that when he was in Jingzhou, about one to two thousand were produced each month for dispatch of ten to twenty thousand at a time to Xiangyang and Yingzhou. The Ming Dynasty text Huolongjing describes the use of poisonous gunpowder bombs, including the "wind-and-dust" bomb.