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dis·tur·bance (dĭ-stûrbəns)
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n.
1.
a. The act of disturbing: a disturbance of lake sediments.
b. The condition of being disturbed: “The forest ... is in various stages of disturbance. Only the biggest trees ... have been left standing” (Alex Shoumatoff).
2. Something that disturbs, as a commotion, scuffle, or public tumult.
3. Mental or emotional unbalance or disorder.
4. A variation in normal wind conditions.
5. Geology Folding or faulting that affects a relatively large area.
6. Physics An alteration or displacement of one or more properties of a physical system away from its equilibrium state.
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:

    Indo-European Roots

    Semitic Roots

    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.

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