The range of wavelengths that the human eye can see is from about 400 nm to about 700 nm. Below about 400 nm is the ultraviolet region, and above about 700 nm is the infrared region.
Color is a sensation, a physiological phenomenon.
It is an abstract term much like the term quality or timbre of musical sounds. Objects have color, size, and shape, but wheareas size and shape are distinct properties of the object, color is not. It is a sensory perception of the viewer. The color of an object depends on the light that is emitted from it and that reaches the eye. In the case of opaque bodies, the observed color is due to the light that has been reflected from their surfaces, or emitted from them in the case of luminous bodies.