Derivational etymology. In Apollonius the word is glossed by ἡδύς, the adjective. However, it is clear from other sources that the etymon was assumed to be the verb ἥδομαι, as is regularly the case in etymological derivations by Greek grammarians. It is an epithet of a kind of oil, used as a perfume. The meaning of the adjective is unknown. Therefore different meanings were suggested in Antiquity, following various etymological guesses relating it to words compatible with "oil". This etymology relates it to "sweet". The change from ἥδομαι, ἡδύς, with /ē/ to ἑδανός with /e/, relies on the alternation found in τίθημι ~ τίθεμεν for instance. The fact that the short-vowel derivatives of ἥδομαι have an /a/, not an /e/, was not taken into account, maybe not even noticed.