It is the process a defect follows from discovery to closure. The main stages are: 1. New – Bug is reported. 2. Assigned – Given to a developer. 3. Open – Developer starts working on it. 4. In Progress – Actively being fixed. 5. Fixed – Code changes are done. 6. Retest – QA tests the fix. 7. Verified – Fix is confirmed. 8. Closed – Bug is resolved and closed. 9. (Optional) Rejected, Duplicate, or Reopened – Based on validation outcome.