Code

Computer instructions and data definitions expressed in a programming language or in a form output by an assembler, compiler or other translator.

Defect ( Fault, Bug )

A flaw in a component or system that can cause the component or system to fail to perform its required function, e.g. an incorrect statement or data definition. A defect, if encountered during execution, may cause a failure of the component or system.

Error ( Mistake )

A human action that produces an incorrect result.

Failure

Deviation of the component or system from its expected delivery, service or result.

Quality

The degree to which a component, system or process meets specified requirements and/or user/customer needs and expectations.

Risk

A factor that could result in future negative consequences; usually expressed as impact and likelihood.