Stakeholder (glossary)
(1) Party having a right, share or claim in a system or in its possession of characteristics that meets that party's needs and expectations. (ISO/IEC 2008)
(2) Individual or organization having a right, share, claim, or interest in a system or in its possession of characteristics that meet their needs and expectations; N.B. Stakeholders include, but are not limited to end users, end user organizations, supporters, developers, producers, trainers, maintainers, disposers, acquirers, customers, operators, supplier organizations and regulatory bodies. (ISO/IEC June 2010)
(3) An individual, team, or organization (or classes thereof) with interests in, or concerns relative to, a system. (ISO/IEC 2007)
Source
(1) ISO/IEC. 2008. Systems and Software Engineering - System Life Cycle Processes. Geneva, Switzerland: International Organization for Standardization (ISO)/International Electronical Commission (IEC), ISO/IEC 15288:2008 (E).
(2) ISO/IEC. June 2010. Software and Systems Engineering -- Life Cycle Processes -- Requirements Engineering. Geneva, Switzerland: International Organization for Standardization (ISO)/International Electronical Commission (IEC), ISO/IEC CD 29148.
(3) ISO/IEC. 2007. Systems Engineering--Application and Management of the Systems Engineering Process. Geneva, Switzerland: International Organization for Standards (ISO)/International Electronical Commission (IEC), ISO/IEC 26702:2007.
Discussion
Discussion as to why this is the "consensus" definition for the SEBoK.