A "Daisy Cutter" is a huge bomb that can cause massive destruction.
The blast is so horrific that one of the main reasons merely for threatening its use against an enemy is psychological.
In the Gulf War, US aircraft dropped leaflets on Iraqi troops depicting a huge bomb, with the slogan "Flee and Live, or Stay and Die!"
The type depicted in the leaflets, and also used in Afghanistan, is the BLU-82B Commando Vault or Big Blue 82, also known as the Daisy Cutter.
Some say the name derives from the blast pattern it leaves when viewed from above. Others say it is a much older term for any bomb designed to cut down infantry.
According to the US Air Force, 11 of these were dropped on Iraq during the Gulf War.
They were used in the Vietnam War for creating instant helicopter landing sites in dense jungle.
The bomb's warhead contains 12,600 lb (5,700 kg) of GSX, a slurry of ammonium nitrate - the basis of nitrogen fertiliser - highly flammable aluminium powder, and polystyrene-based soap as a thickener.
A Daisy Cutter is so big that it can be "launched" only by pushing it out of the open back door of a transport plane - typically the MC-130 special forces version of the Hercules is used.
The bomb descends under a stabilising parachute and is detonated just above the ground by a 38-in (97 cm) fuse, which sticks out of its nose.
When it explodes, it generates a massive pressure wave. Ordinarily, atmospheric pressure is about 100,000 pascals (the equivalent of 1kg of force applied to an area of one square cm ¿ or 14.2psi). In a Daisy Cutter explosion, the pressure reaches about 7,000,000Pa (70kg/sq cm - 1,000psi) at the centre.
The effects are felt over an area typically reported to be the size of several football pitches.