.. Continuing the Beginners Guide to Software Testing series

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