Pantone is a system for matching colors, especially when specifying printing inks.
Why is it important to have a system for identifying specific colors?
In one word: consistency. It is essential that when printing, colors come out the same. From design to print, the results need to be consistent.
When printing a logo for a company, it will be immediately evident if the color of red does not match the exact red of the logo. Each color has a number associated with it in order to communicate precisely which color should be printed. Company branding guidelines typically include the pantone numbers of the colors associated with their logo and branding colors. This again creates consistency when creating and printing collateral intended to represent that company.
The Pantone Matching System, commonly referred to as PMS in the printing world, allows graphic designers, companies, and printers to all collaborate on one project and speak a universal language in regards to color.