K is for Key (opens in new tab)

CMYK is a subtractive colour model commonly used in printing. Letters in the acronym stand for the four colours used in the model: Cyan, Magenta, Yellow and… uhm… blacK? The myth goes that using ‘B’ for black would be confusing (on account of blue and brown existing), so powers that be decided to use the last letter of the word ‘black’ in the acronym. This is not quite true.