Bomb is an explosive weapon, which uses the exothermic reaction of explosive materials to provide extremely sudden and violent energy release. The explosion is mainly caused by the mechanical stress transmitted by the ground and atmosphere, the impact and penetration of the pressure driven projectile, the pressure damage and the impact of the explosion. Bombs have been used in Song Dynasty since the 11th century.

The term bomb is generally not applied to explosive devices for civil purposes, such as construction or mining, although it may sometimes be referred to as a "bomb" by those using it. The military use of the term "bomb", or more specifically air bomb operations, usually refers to the most commonly used air dropped non powered explosive weapons by the air force and naval aviation forces. Other military explosive weapons not classified as "bombs" include grenades, artillery shells, deep-water bombs (used in water), warheads or mines in missiles. In unconventional war, other names can refer to a series of offensive weapons. For example, in the recent conflict in the Middle East, rebel fighters used bombs known as improvised explosive devices (IED) to achieve great effectiveness.