A cartridge that does not have enough or any powder charge that sends the bullet part way down the bore. A shooter usually notices it because the shot is not as loud as normal and there is no recoil. The shooter must stop shooting, unload the gun, and remove the bullet from the bore.
A type of fireworks slang for an electric match (see definition of electric match above). True squibs are actually blasting caps (initiators) used in the explosive industry to set off high explosives. This term crept into fireworks jargon by individuals that did not understand the differences between an electric match and a blasting cap. True squibs are not used for fireworks.
A squib is a small explosive device which has a wide range of uses, such as generating mechanical forces as well as in pyrotechnic use. A squib can range in size from 2 to 15 millimetres in diameter. The squib, being an explosive device, releases a lot of energy, and can be used for shattering, triggering, propelling and cutting a wide range of materials.
In linguistics, a squib is a short article that is intended to ignite thinking and discourse by others on topics of theoretical importance - e.g., see MIT Press's journal, Linguistic Inquiry http://mitpress.mit.edu/catalog/item/default.asp?ttype=4&tid=6. Generally, squibs outline anomalous data but do not suggest a solution.