Tonal directions: Cool
A Cool dominant tonal direction is one in which the primary, most important aspect of a person's skintone is that it has a cool (blue) undertone, and needs cool toned colours to look its best. A Cool dominant person might be either a Winter or a Summer in seasonal palette terms, depending on their secondary tonal direction, as illustrated below.
As you can see, the tonal direction Cool always translates to either a Summer or a Winter palette, as both these are typified by cool toned (blue based) colours. The secondary tonal direction dictates which of the two palettes it falls into.