What is meant by Gold plating?

Gold plating in project management or development is when you continue to work on a project past the original intended scope required by the customer. This is often done because the developer believes the customer will be impressed or pleased with the added features, however this only introduces new risks and added time investment to test the new features, maintain them, resolve any issues, etc.

every work that has been done and produce something more than  project commitment is gold plating. it provides the product higher that customer expectation.