Iärnfil
Old Swedish Dictionary - iärnfilMeaning of Old Swedish word "iärnfil" (or iærnfil) in Swedish.
As defined by K.F Söderwall's dictionary of Medieval Swedish:
Orthography: Early Old Swedish used different letters for ä and ö, so iärnfil may have also been written as iærnfil
Possible runic inscription in Medieval Futhork:ᛁᛅᚱᚿᚠᛁᛚ
Medieval Runes were used in Sweden from 12th to 17th centuries.