Wiktionary
n. an improvised explosive device consisting of blasting powder encased in a metal pipe to increase the blast effect.
WordNet
n. a small homemade bomb usually contained in a metal pipe
Wikipedia
A pipe bomb is an improvised explosive device, which uses 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 potentially lethal shrapnel.
Premature detonation is a hazard of attempting to construct any homemade bomb, and the materials and methods used with pipe bombs make unintentional detonation incidents common, usually resulting in serious injury or death to the assembler.
In many countries, the manufacture or possession of a pipe bomb is a serious crime, regardless of its intended use.
Usage examples of "pipe bomb".
He turned to Filmore and held up a long cylindrical device that looked like the offspring of a pipe bomb and a combination lock.
He stood up and heard a pop in his shoulder - a familiar reminder of a black-powder pipe bomb he'd gotten a little intimate with a couple of years back.
To their obvious amazement, he then proceeded to demonstrate the entire process of making a pipe bomb from start to finish.