The form λίς was deemed Aeolic by Greek scholars (D Scholion Il. 17.109). This etymology relies first on the iotacizing pronunciation of [ei] in Roman Greek, so that λεῖος was pronounced [lios], from which it was easy to derive λίς. Secondly, it relies on the fact that there are two different words λίς, one referring to the lion, and another one, an adjective used in Homer as the epithet of the rock and meaning "smooth" (Od. 12.79): the etymology aims at combining the two different meanings by deriving "lion" from "smooth". It is a descriptive etymology, referring to the formal aspect of the lion (and, for that matter, of many other animals…). It is one of the exegetical scholia, found both in A and in the bT scholia, which makes it no later than the 6th c.