Definition - What does Screensaver mean?
A screensaver is a computer application that blanks the screen of the computer when it is inactive or fills it with images or patterns. Originally designed to avoid phosphor burn-in on plasma and CRT monitors, it is now mostly used for security, showing system information, entertainment and other functions.
Techopedia explains Screensaver
Screensavers can be written in various programming languages or designed using a variety of tools. When the system becomes idle, the operating system activates the screensaver, which causes the physical display screen to either go blank or be overlaid with graphics as provided in the display settings. The screensaver is terminated when the mouse is moved or a key on the keyboard is pressed. Sometimes it may ask for a password before returning control to the user.
Computer settings allow users to set the amount of time of inactivity before activating the screensaver as well as the type of screensaver to display.
Screensavers were originally intended to prevent phosphor burn-in on legacy monitors - on these monitors, if a static image remained on a screen for too long, that image could become permanently "burned" onto the screen. With the improvements in display technology, this problem has been minimized or eliminated, and screensavers are now used for different purposes. One of the these is for activating a background task, such as a virus scan or other scheduled applications. The advantage here is that system resources are used only when the system is idle, and thus user productivity is not affected. Screensavers in most corporate organizations make use of automated workstation password protection. This helps in protecting user and company data. For most home users, screensavers serve an entertainment purpose.