Source : Free On-Line Dictionary of Computing

regression testing
     
         Part of the test phase of software development
        where, as new {modules} are integrated into the system and the
        added functionality is tested, previously tested functionality
        is re-tested to assure that no new module has corrupted the
        system.
     
        [Bennatan, E.M., "Software Project Management", 2nd edition,
        McGraw-Hill International, 1992].
     
        (1995-12-04)