In physics, the minimum amount of fissionable material required to sustain a chain reaction.Of a software product, describes a condition of the software such that fixing one bug introduces one plus epsilon bugs.(This malady has many causes: creeping featurism, ports to too many disparate environments, poor initial design, etc.)When software achieves critical mass, it can never be fixedit can only be discarded and rewritten.[Jargon File](1994-12-23)