The Free On-line Dictionary of Computing (30 December 2018):

colour palette
CLUT
colour look-up table
palette

    (colour look-up table, CLUT) A device
   which converts the logical colour numbers stored in each
   pixel of video memory into physical colours, normally
   represented as RGB triplets, that can be displayed on the
   monitor.  The palette is simply a block of fast RAM which
   is addressed by the logical colour and whose output is split
   into the red, green and blue levels which drive the actual
   display (e.g. CRT).

   The number of entries (logical colours) in the palette is the
   total number of colours which can appear on screen
   simultaneously.  The width of each entry determines the number
   of colours which the palette can be set to produce.

   A common example would be a palette of 256 colours
   (i.e. addressed by eight-bit pixel values) where each colour
   can be chosen from a total of 16.7 million colours (i.e. eight
   bits output for each of red, green and blue).

   Changes to the palette affect the whole screen at once and can
   be used to produce special effects which would be much slower
   to produce by updating pixels.

   (1997-06-03)