A Terminal Server (TS) is a server used to run programs instead of running individual copies of the same programs on workstations/local computers. This approach provides a centralized management of updates, ensures that all users have the same version and edition of the programs, and makes it possible for any users of the domain to access those programs from any workstation while they get the experience of having an own copy of the programs with their own settings (e.g., mailbox and signatures in Outlook).
Terminal Servers allow workstations and thin clients to perform program execution, data processing, and data storage on the server. Programs are installed only once (on the server), rather than on every desktop individually.
Terminal Servers are recommended for offices with more than 5 users. They provide efficiency, reliable software distribution, and advanced resource utilization.