multiuser
also: multi-user, time-sharing
A system property that allows multiple users to access and use the same computer simultaneously, each with their own login session, files, and processes.
Multiuser is a fundamental characteristic of Linux and Unix systems, enabling many different users to work on the same machine at the same time without interfering with each other. Each user has a unique login account with their own home directory, permissions, and environment variables.
When multiple users are logged in—whether locally at different terminals or remotely via SSH—the kernel manages their processes and resources independently. User A's files remain private from User B unless explicitly shared, and each user's running processes are isolated.
For example, on a Linux server, User 'alice' and User 'bob' can both be logged in simultaneously, each running their own applications. Alice's processes won't crash Bob's session, and Alice cannot read Bob's private files unless Bob grants permission. This is enforced through the uid/gid (user ID/group ID) system.