Refactoring

a programming practice that allows programmers to improve the structure of a program without making functional changes.

— DevOps for the Modern Enterprise, Mirco Hering

Refactoring is the process of improving the technical internals of a system without changing its outward functionality that users of the system see. It is done to reduce technical debt, keeping the system nimble and less likely to have defects. Often it involves simplifying code or making it fit standard patterns or conform to design standards. It is a normal part of IT system delivery, as technical debt develops naturally over time and must be addressed or else it will lead to longer delivery cycles, more defects, or potential security vulnerabilities.

— War and Peace and IT: Glossary, Mark Schwartz

As the needs of the design shift, it’s often necessary to modify existing code without changing its functionality. This process is called Refactoring

— The (Delicate) Art of Bureaucracy, in “Appendix A”, Mark Schwartz

refactoring means improving the code without changing what it does

— A Seat at the Table, in “3 - A Nimble Approach To The Table”, Mark Schwartz