LCD, or Liquid Crystal Display, is a type of display that uses liquid crystals to show images.
LCD is a generic term for this type of display, which can come in the form of TVs or computer monitors.
LCDs work by using a combination of a backlight, polarizers, liquid crystals, and color filters. By adjusting the amount of electricity the goes to the liquid crystals, the LCD can control the color of each pixel.
Here's a video that breaks down this process: