from The American Heritage® Dictionary of the English Language, 4th Edition
- n. An arbitrary order or decree.
- n. Authorization or sanction: government fiat.
from Wiktionary, Creative Commons Attribution/Share-Alike License
- n. An authoritative command or order to do something; an effectual decree.
- n. A warrant of a judge for certain processes.
- n. An authority for certain proceedings given by the Lord Chancellor's signature.
- v. To make (something) happen.
Medieval Latin, from Latin, let it be done, third person sing. present subjunctive of fierī, to become, to be done; see bheuə- in Indo-European roots.(American Heritage® Dictionary of the English Language, Fourth Edition)
Latin fīat ("let it be done"). (Wiktionary)