1. The event or time of the disappearance of the upper circumferential edge of the sun as it sets below the horizon.
2. The sky as the sun sets: a rosy sunset.
3. A decline or final phase: the sunset of an empire.
4. Law The automatic expiration of a statutory provision on a previously established date, in the absence of reauthorization: The law's sunset was July 1.
Law Providing for an automatic expiration.
v. sun·set·ted, sun·set·ting, sun·sets
To expire on a previously established date, as a statutory provision.
To provide for the expiration of (a program or agency) by means of a sunset provision.
[Adj. and v., on the model of SUNSHINE (as in sunshine law).]
The American Heritage® Dictionary of the English Language, Fifth Edition copyright ©2022 by HarperCollins Publishers. 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.