Axiom is  a general purpose Computer Algebra system. It is useful for research and development of mathematical algorithms. It defines a strongly typed, mathematically correct type hierarchy. It has a programming language and a built-in compiler.
Polybutylene is simply a type of plumbing material that was manufactured between the late 70's and early 90's. It is thought that it was installed in over 6 million homes during that time period.
PBG (Chicago Gang) PBG (Pooh Bear Gang) (formerly Insane Cutthroat Gangsters) is a set of the Gangster Disciples located in Chicago, Illinois. This set of the Gangster Disciples gained some notoriety after the shooting death of one of its members, a drill rapper that went by the name Young Pappy.