Àci (Aci Bonaccorsi, A. Castello, A. Catena, A. Platani, Acireale, A. San Filippo, A. Santa Lucia, A. Sant’Antonio, A. Trezza, in the province of Catania), Sicilian Iàci, also name of a river, silted up by the 1169 Etna eruption: Greek Ἄκις (renowned for its cold water: Ἄκις ποταμός: ἐπὶ τῶν ἄγαν ψυχρῶν. ψυχρὸς γάρ ἐστιν οὗτος, Dĭŏgĕnān. II, 74 = Ăpŏst. I, 96, cfr. III, 12; Ărsĕn. II, 54) *ắk̑ĭ-s) ‘sharp’ (of biting cold), adjective of *haăk̑ĭ́-s *ăk̑ĭ́-s > Greek ἀκίς ‘point, ‘prickly object’. Other Sicel etymologies: Σῐκελοί , Sĭcŭlī ← Σῑκανοί < Proto-Indo-European *G̑ắu̯[ha]dɦŏ-s / *Gắu̯[ha]dɦŏ-s ← √*g̑ĕhau̯(-dɦ)-/√*gĕhau̯(-dɦ)- ‘rejoice’; Αἴτνη < Sicel *Ăi̯tnā < Proto-Indo-European *Haắi̯t-năha ← √*haăi̯-t- ← root √*haăi̯- ‘burn, shine’; maf(f)ia (Pre-Norman anti-feudal defence) < Regional Latin *măgfĭhă < *măg[ŏ]fĭhă < Sicel *măgŏ–̊fĭhā < Proto-Indo-European *m̥g̑-ŏ–̊dɦĭg̑ɦ-ă·ha ‘great protection’ (of Neolithic origin).