A Dispersion (Chemistry) where the dispersed phase has particles in which all dimensions are smaller than approximately one nanometer (so that they aren't colloidal).
https://en.wikipedia.org/wiki/Solution
a solute is a substance dissolved in another substance, known as a solvent
See Thermodynamics of liquid-liquid unmixing
The solution-diffusion model: a review
http://www.bbc.co.uk/education/guides/zgbqtfr/revision
If the solute is white (eg sodium chloride) then the solution is colourless. This is because the white colour is due to the scattering of light alone, without absorption of any wavelength.
If the solute is coloured (eg blue copper sulfate) then the solution will have a colour.