A computer terminal or data terminal is a device made up of a display unit and a keyboard. It is used to access a computer system in order to run programs and manage computer files. Terminals output only characters, not graphics.
They were developed from teletypewriters. At that time, computers were still very bulky and did not yet have a computer monitor or keyboard on its own.
Some technical terms are:
terminal identity = a unique code to provide identification and authorization of a user.
terminal interface = a text-based user interface to access computers.