IED stands for "Improvised
Explosive Device", and is a term currently used by US forces in
Iraq and
Afghanistan to describe the roadside bombs that are constantly being planted and detonated by the local
insurgents. The term has now spread to other places, but was
coined in Iraq due to the fact that improvised bombs first became a real tool of
war in that theater. Improvised bombs have always been around, but the
acronym-happy US military needed a consistent descriptor to use in reports.
Terms previously used for such guerrilla devices like "car bomb", "time bomb", "suicide bomb" and others don't apply, as the mechanisms and tactics involved are significantly different. IEDs differ mostly in that they are triggered remotely (instead of by a timer, fuse, deadman switch, or such) by an insurgent hiding nearby to ensure that the target (US Troops, coalition forces, and allied Iraqi police and military) are as close as possible to the blast to gain the maximum destructive impact. Countermeasures include radio jamming (unfortunately ineffective against wired remotes), using robots to investigate and remotely detonate suspicious packages/mounds/bushes etc.