I don't know about Indonesian language; but, i know the italian language word comes from the Latin Gratiis, ablative plural of the noun Gratia. It means "for the favor, thanks to goodwill" and by extension "for free".
Yep, "gratis" means in many European languages "for free, costless". Gratia, gratii, yes sir, many international words come from Latin. Italian "grazia" (=thanks) must obviously have this same origin too?
Thanks for this very nice faucet too.