A color lookup table (LUT) is a file that maps the colors in a video file to output colors. This is often used when taking footage shot in different profiles such as CineLike or LOG and doing a basic grade to Rec709.
There are also “look” LUTs for adding stylized looks to your footage such as orange/teal, scifi, and others.
This video will serve as an introduction to installing and usings LUTs for your footage.