What does 
User Acceptance Testing (UAT) mean?
User acceptance testing (UAT) is the last phase of the software testing process that verifies whether a product or software is fit for the purpose it was built for in the first place—namely, that it:

  • Fulfills business requirements
  • Can be used by end-users

During UAT, people (often from the demographic the software is designed for) test the software to make sure it can handle required tasks in real-world scenarios, according to specifications.
UAT is one of the final and most critical software project procedures that ensures developed software is ready to be rolled out to the market.
UAT is also known as beta testing, application testing or end-user testing, and it's the final testing performed after the functional, system, and regression testing stages are over.