Explain defect life cycle

It is basically finding the defect, reporting it on, assigning it, solving the problem, testing again to make sure everything is OK and then closing the defect.

Defect life cycle is the process in which the status of the defect comes in to picture. It gives different stages of the defect. i.e whether it is opened,closed or canceled. The defect life cycle is:

first when the defect is found  (this is called the New stage)
then it is sent to the developer (this is called the Open stage)
once the developer fixes and sends back to the tester (it is called as Fixed)
now the tester checks if the bug had been fixed , if it is fixed (it is called Closed)
if the bug is not fixed it is returned back to the developer (this is called as Reopen)