aberration

UK: /ˌæbəˈreɪʃ^ən/ US: /ˌæbəˈreɪʃən/ ,(ab′ə rā′shən)

WordReference Random House Learner's Dictionary of American English © 2026

ab•er•ra•tion /ˌæbəˈreɪʃən/   n. [countable]

1. a way of behaving or acting that deviates from the usual or normal way:
   A warm spell is an aberration in winter.

ab•er•rant /əˈbɛrənt, ˈæbər-/  adj. 
ab•er•ra•tion•al, adj. 

WordReference Random House Unabridged Dictionary of American English © 2026

ab•er•ra•tion  (ab′ə rā′shən), n. 

1. the act of departing from the right, normal, or usual course.
2. the act of deviating from the ordinary, usual, or normal type.
3. deviation from truth or moral rectitude.
4. Psychiatry mental irregularity or disorder, esp. of a minor or temporary nature;
   lapse from a sound mental state.
5. Astronomy apparent displacement of a heavenly body, owing to the motion of the earth in its orbit.
6. Optics any disturbance of the rays of a pencil of light such that they can no longer be brought to a sharp focus or form a clear image.
7. Photography a defect in a camera lens or lens system, due to flaws in design, material, or construction, that can distort the image.

• Latin aberrātiōn- (stem of aberrātiō), equivalent. to aberrāt(us), past participle of aberrāre (see aberrant) + -iōn- -ion
• 1585–95

ab′er•ra′tion•al, adj. 
Synonyms

• 1. wandering; deviation, divergence.
• 4. abnormality, eccentricity, illusion, delusion, hallucination.

Collins Concise English Dictionary © HarperCollins Publishers::

aberration / ˌæbəˈreɪʃən/ noun

1. deviation from what is normal, expected, or usual
2. departure from truth, morality, etc
3. a lapse in control of one's mental faculties
4. a defect in a lens or mirror that causes the formation of either a distorted image or one with coloured fringes
   See also spherical aberration, chromatic aberration
5. the apparent displacement of a celestial body due to the finite speed of light and the motion of the observer with the earth