RE-TESTING: we check for the particular bug and its 
dependencies after it is said to be fixed.
REGRESSION TESTING : We check the entire system whether the 
fixed bug make any adverse effect in the existing system or 
not.

RETESTING: Testing the application with multiple sets of 
test data is Retesting.

REGRESSION TESTING: Test the bug fixes r working properly 
as the specification and test, by fixing these bug any 
other feature may get impacted (conduct impact analysis) is 
regression testing.

Correct me if i'm wrong :)

Jyotsna.

Retesting: The re-execution of test cases on same 
application with multiple test data.

Regression testing: The re-execution of selected test cases 
on modified build to ensure bug fix work.

re testing:re execution of testcases on the modified build 
to ensure that bug is closed or not

regression testing:re execution of testcases on the 
modified build to ensure that resolved bug has made any 
impact on other functionality

hi ,
jyotsna and pranathi are right,,

Retesting : --

reexecution of testcases on same application build with 
different input values is retesting.

regression Testting : 

reexecution of testcases on modify form of build is called 
regression testing..

ok,, bye.

Hi,
 

 Retesting means we are going to check weather the bug is 
fixed or not..

Regression testing means after getting confirmation the bug 
is fixed we are going to check the fixation is going to 
create any problems in the application or not.. that means 
due to the fixation of the bug we got any side effects in 
the application or not..


Regards,
Satya.k

Re Testing:Execution of test cases with different sets of  
Test data(the data may be positive data, negative data or 
we can say valid data or invalid data).

Regression Testing:Re execution of test cases on modified 
build based on bug fix work.

retesting & regression testing:
retesting: retesting is conduct to test different 
combinations of data i.e called retesting
regression testing:regression testing once the tester 
report the bug after the developer resolve the bug and 
developer should assign the build to tester after the test 
engineer should test the build the modifying build is 
working or not this process called Regression Testing

regression testing: in this the deffected functionality and 
its related functionalities are tested to check there any 
new diffects are raised due to that change.

re testing: the diffected functionality only checked 
whether it is rectified or not.