Derivational etymology relying on the fact that what is dry is usually hard, whereas what is moist is not. It implies two formal manipulations. The κράσις invoked refers to the fact that one single grapheme ξ combines two sounds and therefore two letters in the Greek view. Even though ξ was never pronounced [sk], it was, as a double letter, be considered as the fusion both of [sk] and of [ks]: this is one among many instances of the absence of any distinction between the phonological level and the graphic one in Greek etymology.