Defect
A flaw in a software product where the actual behavior deviates from the expected behavior defined by requirements, specifications, or reasonable user expectations. Also commonly called a bug.
A well-documented defect report includes: a clear title, steps to reproduce, expected behavior, actual behavior, environment details (browser, OS, device), severity, priority, screenshots or recordings, and any relevant logs. Good defect reports dramatically reduce the time developers spend diagnosing and fixing issues.
Defects are typically tracked through a lifecycle: New, Assigned, In Progress, Fixed, Verified, and Closed. Defects that cannot be reproduced may be marked as 'Cannot Reproduce,' and those deemed intentional behavior may be closed as 'By Design.'
Why It Matters for QA Teams
Clear, thorough defect reporting is the primary output of QA work. The quality of bug reports directly impacts how quickly developers can fix issues and how confidently the team can ship.
Example
BUG-1287: Order total displays $0.00 when applying a 100% discount code
Steps: 1. Add any item to cart. 2. Apply code 'FREEBIE100'. 3. Proceed to checkout.
Expected: Order total shows $0.00 and checkout proceeds normally.
Actual: Order total shows $0.00 but the 'Place Order' button is disabled because the validation rejects $0.00 as an invalid amount.