fi·at (fēət, -ăt′, -ät′, fīăt′, -ət)
1. An arbitrary order or decree.
2. Authorization or sanction: government fiat.
[Medieval Latin, from Latin, let it be done, third person sing. present subjunctive of fierī, to become, to be done; see bheuə- in the Appendix of Indo-European roots.]
The American Heritage® Dictionary of the English Language, Fifth Edition copyright ©2019 by Houghton Mifflin Harcourt Publishing Company. All rights reserved.
Indo-European & Semitic Roots Appendices
Thousands of entries in the dictionary include etymologies that trace their origins back to reconstructed proto-languages. You can obtain more information about these forms in our online appendices:
The Indo-European appendix covers nearly half of the Indo-European roots that have left their mark on English words. A more complete treatment of Indo-European roots and the English words derived from them is available in our Dictionary of Indo-European Roots.