screensaver
nounUK /ˈskriːnˌseɪvə/
US /ˈskriːnˌseɪvər/
A picture or moving pattern that shows on a computer screen when you are not using it.
The aquarium screensaver swam with colorful fish while the computer sat idle.
OTHER MEANINGS
2. A program that prevents images from being permanently burned into a screen.
Old CRT monitors needed a screensaver to avoid burn-in.
3. A decorative animation shown during inactivity for entertainment.
He set a flying-toasters screensaver to amuse his coworkers.
4. A lock screen or standby display that appears after a period of no activity.
The phone's screensaver showed the time and a slideshow of family photos.