A lot vs. Alot: 9 Grammatical Pitfalls
a display or monitor on which the user selects options with the touch of a finger, stylus, or digital pen
An input device that allows user to interact with computer by touching the display screen.
Often this uses beams of infrared light that are projected across the screen surface. Interrupting the beams generates an electronic signal identifying the location of the screen. Software interprets the signal and performs the required operation.