Refers to the light unit in LCD displays which create the light to display the picture. The backlight unit, or BLU, refers to the light unit in LCD display which creates the light to display the picture on the screen. Most LCD sets use LED backlights either arranged along one or more edges of the screen (edge-lit), or directly behind the screen (direct-lit). Control over these lights also affects how well the TV renders dimming and brightness on different sections (zones) of its display as you’re watching content. A direct-lit backlight that can control the light from different parts of the screen is called a Full Addressed Local Dimming backlight (FALD).
The most sophisticated LCD TVs use miniLED direct-lit backlights which give up to hundreds or thousands of control zones on the screen to display content with a better dynamic range.