I think about an another word in celtic to design the sword "Kladio-= gladius"
Aeliestr- = gladiolus flower (and iris)
Breton = Elestrenn
Old Breton = Elester
Cornique = Elester
Welsh = Elestr
Irish = Feileastar
may be connect with Latin Alestrere = to dampen
but difficulty with Irish form (letter F)
and in this link :
http://www.wales.ac.uk/Resources/Documents/Research/CelticLanguages/EnglishProtoCelticWordList.pdf
Sword-Flag = A/eli/es(t)r- ?
so :
Aeliestr- = gladiolus flower and gladiolus = little sword (gladius) = sword = Aeliestr-
may be similarity between leef gladiolus (flower) and the blade gladius (sword) sharped leef ?
may be connect with Latin Alestrere = to dampen
but difficulty with Irish form (letter F)