What is a "Terminal" in a Computer?
A terminal is, generally, an application with a window with black background and white text where you can type text commands, called terminal commands, which are interpreted by a type of program called shell. In this sense, it's also called a terminal window or console.
date being typed and executed in a window of GNOME Terminal on Linux Mint. The flashing rectangle that appears after the shell prompt is the text cursor.To have a window, we also need a program called a window manager running. If the operating system doesn't have a window manager, the whole screen may become a single terminal, i.e. the entire screen would be black with white text for you to type terminal commands.
Physical Terminals
In the past, computers weren't capable of displaying images, only text, and even the screen resolutions weren't measured in pixels, but in the maximum number of columns and lines of text that could be display at a given moment. In this era, physical computers (the hardware) were called terminals. These days, "physical terminal" is a phrase that is used in this sense.
Teletypewriters
Before terminals had monitors, they were teletypewriters that physically printed the output of programs on paper.
In this case, the input such as the command-line is also printed on paper. This seems to be the reason why passwords, for example, appear as asterisks (*) on terminals: the teletypewriter sent the key presses to the computer it was connected to, which could optionally respond by telling the TTY to print an asterisk to confirm it received the key press.
![A teletypewriter device printing terminal messages on a piece of paper. The messages read in all caps: CONNECTION CLOSED BY FOREIGN HOST. CONNECTION TO TTY.LIVINGCOMPUTERMUSEUM.ORG CLOSED. % % % % TELNET 192.168.251.28 TRYING 192.168.251.28... CONNECTED To 192.168.251.28. ESCAPE CHARACTER IS '↑]'. UNIX (R) SYSTEM V RELEASE 4.0 (AMIX) LOGIN: GUEST PASSWORD: UNIX SYSTEM V RELEASE 4.0 AT&T AMIGA (UNLIMITED). AMIX COPYRIGHT (C) 1984, 1986, 1987, 1988 AT&T ALL RIGHTS RESERVED LAST LOGIN: TUE MAY 7 05:11:17 FROM LOCALHOST LAST LOGIN: TUE MAY 7 05:11:17 FROM LOCALHOST SYS (text ends here)](https://www.virtualcuriosities.com/wp-content/uploads/2025/03/teletypewriter-printing-terminal-messages-20250326-300x237.webp)
Usually, the term "terminal" is reserved for terminals with monitors, with teleprinters being thought of as separate, but in the past it seems this wasn't the case.
Computer room is fascinating
BY ROBERTA MAHONEY
You may not realize it yet, but there is a computer room on the third floor of the Science Mathematic Building, just waitint [sic] to be explored by you.
The lab was nine teleprinters and one C.R.T., (all called terminals), connected to one computer. The teleprinters are a little different from the C.R.T., in that they are noisier and slower. The computer controls all data, and is the central processing unit.
Lariat, Volume VI, Number 11, 2 May 1975 [https://cdnc.ucr.edu/?a=d&d=LAR19750502.2.18&e=-------en--20--1--txt-txIN--------] (accessed 2025-03-26)