An Etymological Dictionary of the German Language/Harnisch

by Friedrich Kluge

Harnisch, m., ‘harness, armour,’ from MidHG. harnasch, variants harnas, harnesch, n., ‘harness’; borrowed at the end of the 12th cent. from OFr. harnais, ‘armour, gear,’ which has come to be a common Rom. term (Ital. arnese), but may be traced probably to a Kelt. source (W. haiarnaez, ‘iron utensils’); the connecting link might be MidE. harnez, ‘armour’ (E. harness).