Local Contrast Enhancer is a picture technology that adjusts brightness in different parts of the screen to make details clearer.
It makes dark scenes show more texture without making them too bright, and bright scenes look sharper without washing out colors.
For example, when watching a night scene in a movie, you can still see the details in a black jacket while streetlights look bright and natural.
See also: Local Dimming, HDR, Contrast Ratio.