**defects** =The variation in the expected and actual results is known as defects

**error** =Any incorrect human action that produces a problem in the system is caller error.

**failure** =External behavior is incorrect

**incident** =incident is Any event occurring during testing(we found a defect)

**incident_logging** =keep the record of what we observed and can follow up the incident and track what is done to correct it.

**incident_report** =After logging the incidents that occur in the field-> reporting, tracking, and managing them.

**root_cause** = main cause for the defect,error

**root_cause_analysis** =Root Cause Analysis (RCA) is about identifying the root causes of faults or problems and addressing them instead of treating the symptoms.