In information technology, end-user (alternatively spelled, end user; also known as final user, ultimate user, and ultimate consumer; hereinafter, the User) is any individual who is user of any marketable or system and who is not its developer, installer, and/or service officer. Service officers are called power users; they use advanced features, which are not routinely used by the average end-user. However, service officers don't change the marketable or system; they change its settings or its parts. Developers change.
According to Managing Quality by Foster (6th edition),
- End user. The ultimate user of a product or service.
According to the BABOK Guide (3rd edition),