fiat

American  

[fee-aht, -at, fahy-uht, -at] / ˈfi ɑt, -æt, ˈfaɪ ət, -æt /

noun

1. an authoritative decree, sanction, or order.

   a royal fiat.

   Synonyms:

   ukase, diktat, mandate, ruling, directive, authorization

2. a fixed form of words containing the word fiat, by which a person in authority gives sanction, or authorization.

3. an arbitrary decree or pronouncement, especially by a person or group of persons having absolute authority to enforce it.

   The king ruled by fiat.

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fiat British  

/ ˈfaɪət, -æt /

noun

1. official sanction; authoritative permission

2. an arbitrary order or decree

3. literary any command, decision, or act of will that brings something about

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Etymology

Origin of fiat

First recorded in 1625–35; from Latin: “let it be done,” 3rd-person singular present subjunctive of fierī “to become”

Example Sentences

Customers can use the platform to manage both fiat currency and stablecoins—cryptocurrencies pegged to the U.S. dollar or other assets—allowing for 24/7 operations.

From Barron's • Apr. 2, 2026

If the justice were genuinely worried about this possibility, one would not expect him to erase a key safeguard against it by judicial fiat.

From Slate • Feb. 24, 2026

Wars are financed by borrowing and printing money which devalues debt and fiat currency.

From MarketWatch • Feb. 16, 2026

Their price is meant to be fixed to a fiat currency, typically the U.S. dollar.

From The Wall Street Journal • Feb. 13, 2026

The question caught me by surprise; I had been waiting for a fiat, and now a choice lay before me.

From "Black Boy" by Richard Wright