(1) Termination of the ability of a product to perform a required function or its inability to perform within previously specified limits. (ISO/IEC 2005, 4.2)
(2) An event in which a system or system component does not perform a required function within specified limits. (ISO/IEC/IEEE 2009, 1)
(3) The event in which any part of an item does not perform as required by its specification. The failure may occur at a value in excess of the minimum required in the specification, i.e., past design limits or beyond the margin of safety. (INCOSE 2012)
(1) ISO/IEC. 2005. Software Engineering - Software Product Quality Requirements and Evaluation (SQuaRE) - Guide to SQuaRE. Geneva, Switzerland: International Organization for Standardization (ISO)/International Electrotechnical Commission (IEC). ISO/IEC 25000:2005.
(2) ISO/IEC/IEEE. 2009. Systems and Software Engineering - System and Software Engineering Vocabulary (SEVocab). Geneva, Switzerland: International Organization for Standardization (ISO)/International Electrotechnical Commission (IEC)/ Institute of Electrical and Electronics Engineers (IEEE). ISO/IEC/IEEE 24765:2009.
(3) INCOSE. 2012. Systems Engineering Handbook: A Guide for System Life Cycle Processes and Activities, version 3.2.2. San Diego, CA, USA: International Council on Systems Engineering (INCOSE), INCOSE-TP-2003-002-03.2.2.