This is the darkness or lightness of a particular color.
Shades are the relative darkness of a color and Tints are the relative lightness of a color.
It is important to note Intensity of a color here because a value of, lets say, red can be the same as a medium TONE of that same color. A Tone can be the same value, but can be grayed in such a way that it is not at the highest degree of Intensity. This is illustrated in the middle ring of the Color Wheel above. The outer ring of Shades illustrates what happens to a Pure Hue when black is added. The center section of Tints shows the effect of white on the Pure Hue.