smol·der also smoul·der (smōldər)
intr.v. smol·dered, smol·der·ing, smol·ders also smoul·dered or smoul·der·ing or smoul·ders
1. To burn with little smoke and no flame.
2. To exist in a suppressed state: Revolution smoldered in the masses.
3. To show signs of repressed anger or hatred.
Thick smoke resulting from a slow fire.
[Middle English smolderen, to suffocate, from smolder, smoke, probably alteration of smorther, from Old English smorian, to smoke.]
The American Heritage® Dictionary of the English Language, Fifth Edition copyright ©2020 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.