Building on a so far neglected root-etymology by Boisacq (1923), the present paper proposes to analyze the Greek adverb ἅλις ‘in abundance, in throngs; enough’ (~ Hesychian gloss γάλι ‘enough’) as the lexicalized locative singular of a mobile root noun PIE *su̯élH- / *su̯l̥H-́ ‘swelling, bulging’ ⇒ ‘heap’, belonging to the PIE root *su̯elH- ‘to swell’.