Informal term for Defect. See defect.
A Software Defect / Bug is a condition in a software product which does not meet a software requirement (as stated in the requirement specifications) or end-user expectations (which may not be specified but are reasonable). — http://softwaretestingfundamentals.com/defect/
- When the result of the software application or product does not meet with the end user expectations or the software requirements then it results into a Bug or Defect. These defects or bugs occur because of an error in logic or in coding which results into the failure or unpredicted or unanticipated results.
- When actual result deviates from the expected result while testing a software application or product. Hence, any deviation from the specification mentioned in the product functional specification document is a defect.
- By definition a defect is a missing functionality.
- The definition assumes the existence of a software requirement or specification.
- Many definitions make allowances for situations where a perfectly reasonable requirement has not been formally stated. This injects an element of judgement into the definition in order to allow for imperfect or incomplete statement of requirements.
A failure is the symptom, the behavior observed in testing, that indicates there is an error/defect in the code.