Failure
When the software visibly does something wrong while it is running.
Definition
A failure is an event where the system does not do what it should, observed by a user or tester. It happens when defective code is executed. Not every defect causes a failure, for example if the faulty code is never reached.
In practice
The user taps "Pay" and the app crashes. The crash is the failure caused by a defect in the payment code.
Learn it in context
Lessons that use this term.