Fault, Error & Failure

Fault : It is a condition that causes the software to fail to perform its required function.
Error : Refers to difference between Actual Output and Expected output.
Failure : It is the inability of a system or component to perform required function according to its specification.
IEEE Definitions

• Failure: External behavior is incorrect
• Fault: Discrepancy in code that causes a failure.
• Error: Human mistake that caused fault

Note:

• Error is terminology of Developer.
• Bug is terminology of Tester