They all have 3 letters, but "red" and "tan" have exactly 3 letters.
yellow, purple, indigo
PINK BLUE GRAY
Red? -.-
Kangaroo has 8 letters
Some people think letters have particular colors because they have a condition called Synesthesia. A synesthete's brain tends to associate certain letters with colors.
Emerald
A letter cannot have "8 letters" in it.
CornFlower
red and tan
They all have 3 letters, but "red" and "tan" have exactly 3 letters.
Brass is a color. It contains the letters B and S.
Nonsense-8 letters.
Jade, Khaki and Kelly Green are colors.
indigo
red, tan
greyindigonegroginger