An end user is the final or ultimate user of a computer system. After a product has ben programmed and finally developed, he/she is the one who is using the fully developed, marketed and installed product.

The end user has to be distinguished from the developer, programmers, installers and administrators of the product (s. also enclosed picture).

Generally speaking the terms 'user' and 'enduser' mean the same thing.

http://www.webopedia.com/TERM/E/end_user.html

http://www.techterms.com/definition/enduser