Re-Testing: 
   It is a process of validating the defect fix to make sure the fix (Defect fix) is working as expected is k.a., ReTesting.
   
It is also k.a., Confirmation Testing.

Example:

  QA has logged 3 defects in the last build. Dev has fixed all the 3 defects in the next build & given to QA for testing purpose.

Now the new build has 3 things:
1. Old feature OR regression features
2. Newly implementation OR code change
3. Defect fix.


Validating the defect fix to check that the fix is working or not is k.a., Re-Testing.
