Know why cattywampus was trending last week?
A set of standard colours for printing, each of which is specified by a single number. You can buy a Pantone swatch book containing samples of each colour. Some computer graphics software allows colours to be specified as Pantone numbers. Even though a computer monitor can only show an approximation to some of the colours, the software can output a colour separation for each different Pantone colour, enabling a print shop to exactly reproduce the original desired colour.