a simple type of Improvised Explosive Device (IED) or bomb favored by criminals
a small but powerful bomb or explosive
A fragmentation device. Sections of pipe or pipe nipples are filled with explosive, or propellant (gun powder) and closed with end caps through which a fuse has been introduced. When the filler is ignited, the resultant explosion causes the pipe to fail and form fragments. See Bomb, Explosives, Explosion, Propellant.
A pipe bomb is a simple type of improvised explosive device, a tightly sealed section of pipe filled with an explosive material. The containment provided by the pipe means that simple low explosives can be used to produce a relatively large explosion, and the fragmentation of the pipe itself creates lethal shrapnel.