Likely cognate with Ancient Greek εὔληρα (eúlēra, “reins”), Old Armenian լար (lar, “rope, cord”). The strange suffixation of the Greek comparandum suggests a borrowing from some extinct substrate language, though the ē-ō ablaut in the Greek and Latin forms, respectively, suggest said substrate to be Indo-European. Alternatively, possibly from an earlier *vlōrum, from Proto-Indo-European *wel- (“to turn, wind, round”), the same root as of volvō (“to roll”).