Software is part of a system solution that can be encoded to execute on a computer as a set of instructions; it includes all the associated documentation necessary to understand, transform and use that solution [ISERN]
Software is the collection of computer programs, procedures, rules, and associated documentation and data [IEEE]
Software is the non-hardware part, including associated documentation, of a system being implemented or implemented in part with a computer or an embedded processor[Rosen 1992]