Improvised Explosive Device

An improvised explosive device (IED) is a bomb constructed and deployed in ways other than in conventional military action. It may be constructed of conventional military explosives, such as an artillery shell, attached to a detonating mechanism. IEDs are commonly used as roadside bombs.
IEDs are generally seen in terrorist actions or in asymmetric unconventional warfare by insurgent guerrillas or commando forces in a theatre of operations.