fire-brand, Irish, Old Irish aithinne: *aith-tén-io-? Root of teine? The root and, kindle, as in Old Irish andud, accendere, adandad, lighting up, is also possible, *aith-and-io- being the form in that case. amhailte (Glen-moriston).
Etymological dictionary of the Gaelic language.
Alexander Gairm Publications.
1982.