pistole (n.)

1590s, former Spanish gold coin (not so called in Spanish), from French pistole, from Italian piastola, diminutive of piastra "plate or leaf of metal" (see piaster) and said to be so called for being smaller and thinner than the Crown. Compare earlier pistolet (1550s) "foreign coin," which OED says is from French pistolet "short firearm" (see pistol).