noun
pixel defect; dead pixel; stuck pixel
Technical term for a defective pixel on an LCD or similar display; often used in the context of quality checks for monitors, TVs, and smartphone screens. Compare with ドット抜け, which is sometimes used interchangeably.
See also: ドット抜け
新品のモニターにドット落ちが見つかったので、交換してもらった。
I found a pixel defect on the new monitor, so I had it replaced.
ドット落ち
Even a single dead pixel can ruin the impression of the whole screen.