a. The act of deviating or turning aside.
b. An instance of this: "We made so many deviations up and down lanes ... that I was quite tired, and very glad, when we saw Yarmouth" (Charles Dickens).
a. Divergence from an accepted idea, policy, or norm of behavior: "Freud, as the leader of a powerful new movement, could not bear much deviation from his own central ideas" (Joseph Epstein).
b. An instance of this; an abnormality or departure from a norm: "Vice was a deviation from our nature" (Henry Fielding).
3. Deflection of a compass needle caused by local magnetic influence, especially on a ship.
4. Statistics The difference, especially the absolute difference, between one number in a set of data and the mean of that set of data.
de′vi·ation·ist adj. & n.
Synonyms: deviation, aberration, divergence
These nouns mean a departure from what is prescribed or expected: tolerates no deviation from the rules; an act that represented an aberration from his usual behavior; a doctrine seen as a divergence from previous beliefs.
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.