The Universals and Evolution model in cross-language color naming systems (Berlin B, Kay P, Basic color terms. University of California Press, Berkeley, 1969) predicted that Classical Greek chroma terms should have referred to hue regions of the color space. In this article, I propose an original reading of the Plato's Timaeus (67c68d) that provides additional support to that prediction. It also shows that he was well aware of the distinction between saturation, brightness and hue.