Объединяющее свойство - отсутствие цвета.
In Anglo-Saxon, BLACK is blaece and WHITE is blac (so we get blanch, blank, bleak).
They both based on a common feature - absense of color.
Accordingly to anthropologists, words for colors enter in to a culture's vocabulary in strict sequence:
All languages have BLACK or WHITE. (color of night, color of mourning, color of nothing)
If there are three words, then comes RED. (blood?)
After that, GREEN or YELLOW.
The fifth is either YELLOW or GREEN, depending on the fourth word.
The seventh, BROWN.
After that comes PURPLE, PINK, ORANGE, and GREY in no particular order.
taken from patchmonkey.net