1. A deviation from what is typical or normal: an election that was an aberration from usual state politics. See Synonyms at deviation.
2. A departure from what is considered natural or proper: "Throughout history, the beast with a taste for human flesh has been regarded as an aberration, even as an outlaw" (Philip Caputo).
3. An abnormal, usually temporary alteration in one's mental state.
a. A defect of focus, such as blurring in an image.
b. An imperfect image caused by a physical defect in an optical element, as in a lens.
5. The apparent displacement of the position of a celestial body in the direction of motion of an observer on Earth, caused by the motion of Earth and the finite velocity of light.
6. Genetics A deviation in the normal structure or number of chromosomes in an organism.
[Latin aberrātiō, aberrātiōn-, diversion, from aberrātus, past participle of aberrāre, to go astray : ab-, away from; see AB-1 + errāre, to stray; see ers- in the Appendix of Indo-European roots.]
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.