A function key is a key on a computer or terminal keyboard that can be programmed to cause the operating system or an application program to perform certain actions, a form of soft key. On some keyboards/computers, function keys may have default actions, accessible on power-on.
Flexowriter keyboard (1968) with 13 function keys on the right
Keyboard with 24 function keys
A computer terminal is an electronic or electromechanical hardware device that can be used for entering data into, and transcribing data from, a computer or a computing system. The teletype was an example of an early-day hard-copy terminal and predated the use of a computer screen by decades. Starting in the mid-1970s with machines such as the Sphere 1, Sol-20, and Apple I, terminal circuitry began to be integrated into personal and workstation computer systems, with the computer handling character generation and outputting to a CRT display such as a computer monitor or, sometimes, a consumer TV.
A Teletype Model 33 ASR teleprinter, usable as a terminal
Closeup of an IBM 2741 printing terminal, which used a changeable Selectric "golfball" typing element and was faster than the earlier teletype machines
IBM 2260
ADM-3A