Any deviation from defined standards. Same as defect.
What is Cause-and-Effect (Fishbone) Diagram?
What is Control Chart?
What is V- Diagram (model)?
What is Customer (end user)?
What is Defect Analysis?
What is Desk Checking?
What is Execution?
What is Fault Tree Analysis?
What is Heuristics Testing?
What is Infeasible Path?