Look-up Table (LUT)
A table mapping input colour values to output values, used to apply a colour transformation quickly and repeatably.
In depth
Rather than calculating a transformation for every pixel, a LUT stores the answers and interpolates between them, which is fast enough to run in real time on camera monitors. LUTs serve two distinct roles: technical conversion, such as taking log footage into a standard space, and creative looks applied for style.
Examples in practice
A monitoring LUT lets a camera operator see a graded image on set while recording a flat log file.