Color is light with wavelengths in the electromagnetic spectrum that the human eye can see. The range is roughly from 400 – 750 nm.
Colors are typically defined by either the CIE RGB or CIE XYZ system.
The benefit of a standardised color system is that the color of a certain object can be described in an objective manner. Such that an instrument can be used to check that the color of a fabric, car paint or OLED display is guaranteed to be the same always.