Quality is delighting customers
Re Testing: Means Testing on a fixed defect, to test weather it is fixed or not.
Regression Testing: Testing Conducted on a modified build/application is called Regression testing. (To fix the defect the developer may changed some functionality in the application build, our intension is that the changed functionality may has some effect some other functionality. that is our intension we are conducting Regression testing.)
Re-Testing:After a defect is detected and fixed, the software should be retested to confirm that the original defect has been successfully removed. This is called Confirmation Testing or Re-Testing
Regression Testing :is the repeated testing of an already tested program, after modification, to discover any defects introduced or uncovered as a result of the change(s)
My Reference....ISTQB Foundation Level
Re-Testing: While executing a test case you found a bug...Once it is fixed then you will execute the same test case whether it is going fine or not, this is called retesting.
Regression Testing :Regression testing is nothing but checking the impacted modules because of these bug fixes and added new functionalities.
Re-testing : Its nothing but verifying whether the already logged bug is being fixed or not after the bug fix is made and to test nothing more than that.
Regression Testing : This will be carried out to ensure that the newly added or changed functionality/ Modified coding /Integrated module have not affected the existing system and its functionality.
The Difference between Re-testing and Regression testing is:
Re-Testing : In this, tester will test the fixed part of the application only but not the whole application.
Regression Testing : In this , Tester will test the whole application after change has been made to make sure that changes does not effect the previous functionality.