Simple Definition of fiat
: an official order given by someone who has power : an order that must be followed
Examples of fiat in a sentence
He runs the company by fiat.
<the school principal issued a fiat that caps were not to be worn inside the school, and that was that>
Origin and Etymology of fiat
Latin, let it be done, 3d singular present subjunctive of fieri to become, be done — more at be
First Known Use: circa 1631
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