1. An unanticipated or sudden check in progress; a change from better to worse.
a. A steplike recession in a wall. Also called setoff.
b. Any of a series of such recessions in the rise of a tall building.
3. An automatically timed setting of a thermostat to a lower temperature, as in the home at night.
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.