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.
Symbol Pb A soft, easily shaped, heavy, bluish-gray metallic element that is extracted chiefly from galena. It is very durable and resistant to corrosion and is a poor conductor of electricity. Lead is used to make radiation shielding and containers for corrosive substances.