Topic summary
Single user

Extracted from the Wikipedia article Multi-user software.
The complementary term, single-user, is most commonly used when talking about an operating system being usable only by one person at a time, or in reference to a single-user software license agreement. Multi-user operating systems such as Unix sometimes have a single user mode or runlevel available for emergency maintenance. Examples of single-user operating systems include MS-DOS, OS/2 and Classic Mac OS.