A fiat is an order that takes effect purely because whoever holds power wills it so. By fiat, government fiat, rule by fiat.
Fiat money is the important use: paper worth something only because a state says so, which is what all modern currency is. The Latin means let it be done, and the word is unrelated to the car company by anything but coincidence of spelling.
1nounfiatAn order that takes effect purely because whoever holds power wills it so, as with paper money worth something only because a state says so.
“The general ruled by fiat, ignoring parliament and the courts.”
fiat is an order.
Latin fiat means let it be done, from fieri, to become.
Proto-Indo-European
*bʰuH-
Latin
fīat — let it be done
English, today
fiat
From Latin fīat (“let it be done”).
Etymology from Wiktionary, CC BY-SA