This etymology is explicitly attributed to Herodian by a scholion to Aristotle's Categories (see Parallels). It cannot be separated from the etymology given by the same Herodian for σκότος "darkness" (see σκότος / σχέθω), which has a very similar wording to the explanation in the scholion to the Categories. This can be interpreted either as a proof that Herodian considered that σκιά and σκότος had the same etymology, or, which seems more likely, that Herodian gave this etymology for σκότος and glossed the latter by σκιά, from where compilers attributed to σκιά the etymology of σκότος.