From Proto-Italic *fī(s)lom, from Proto-Indo-European *gʷʰiH-(s-)lo- (“sinew”). Cognate with Lithuanian gysla (“vein; thread; nerve”), Proto-Slavic *žìla (“vein; sinew”), Old Armenian ջիլ (ǰil, “sinew”), Sanskrit ज्या (jyā, “bowstring”), Welsh gïau (“sinews”).