[ fee-aht, -at; fahy-uht, -at ]
/ ˈfi ɑt, -æt; ˈfaɪ ət, -æt /
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an authoritative decree, sanction, or order: a royal fiat.
a fixed form of words containing the word fiat, by which a person in authority gives sanction, or authorization.
an arbitrary decree or pronouncement, especially by a person or group of persons having absolute authority to enforce it: The king ruled by fiat.



Call upon your favorite grammar inspirations to tackle this quiz on the differences and uses of "evoke" and "invoke."
Question 1 of 7
“Evoke” and “invoke” both derive from the same Latin root “vocāre.”

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Origin of fiat

First recorded in 1625–35; from Latin: “let it be done,” 3rd singular present subjunctive of fierī “to become”
Dictionary.com Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2021

How to use fiat in a sentence

British Dictionary definitions for fiat

/ (ˈfaɪət, -æt) /


official sanction; authoritative permission
an arbitrary order or decree
mainly literary any command, decision, or act of will that brings something about

Word Origin for fiat

C17: from Latin, literally: let it be done, from fierī to become
Collins English Dictionary - Complete & Unabridged 2012 Digital Edition © William Collins Sons & Co. Ltd. 1979, 1986 © HarperCollins Publishers 1998, 2000, 2003, 2005, 2006, 2007, 2009, 2012