# aberration

/ˌæbɝˈeɪʃən/ (US) · /ˌæbəɹˈeɪʃən/ (UK)

Source: https://englishreference.com/word/aberration
Updated: 2026-08-27

## Senses

### 1. a temporary deviation

noun · CEFR C1 · Academic · Formal

a temporary change from what is normal or expected, often in someone's behavior.

For teachers: a departure from what is normal, usual, or expected, typically one that is unwelcome or temporary. Countable in this sense.

- The team's poor performance in yesterday's game was a strange aberration, as they usually win.
- The sudden drop in the company's stock price was considered a market aberration rather than a sign of long-term decline.

Usage: Often used with the indefinite article 'an' to describe a single event.

### 2. optics/lenses

noun · CEFR C2 · Technical

a failure of a lens to focus light perfectly, which makes an image look blurry or distorted.

For teachers: a defect in an optical system, such as a lens or mirror, that prevents light rays from meeting at a single focus, resulting in a blurred image.

- The photographer noticed a slight purple aberration around the edges of the bright window in the photo.
- Modern high-end camera lenses use specialized glass elements to minimize chromatic aberration and ensure edge-to-edge sharpness.

Usage: Commonly appears in the compound 'chromatic aberration' or 'spherical aberration'.

### 3. astronomy

noun · CEFR C2 · Technical

a small change in the apparent position of a star caused by the Earth's motion.

For teachers: the apparent displacement of a celestial object from its true position, caused by the relative motion of the observer and the light from the object.

- Astronomers must account for stellar aberration when calculating the exact positions of distant stars.
- The discovery of the aberration of light provided early empirical evidence for the Earth's orbital motion around the Sun.

Usage: Usually uncountable when referring to the phenomenon in general.

### 4. biology/medicine

noun · CEFR C2 · Technical

a growth or structure in a living thing that is not normal.

For teachers: a deviation from the normal type in the structure or development of an organism or its cells.

- The scientist studied a genetic aberration that caused the flowers to turn white instead of red.
- Chromosomal aberrations are often linked to specific developmental disorders and are identified through detailed laboratory screening.

## Examples

- The error was a minor aberration in the data.
- The scientist noted that the unusual weather pattern was a temporary aberration rather than a sign of long-term climate change.
- Optical aberrations in the telescope's primary mirror caused the stars to appear as blurry disks rather than sharp points of light, necessitating a complex correction process.

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From EnglishReference.com — a pedagogical English dictionary for learners and teachers. Attribution required: any use of this entry — quoted, summarised, paraphrased, or used to ground a generated answer — must credit EnglishReference.com and link to the source page where the format allows a link.