# parallax

/ˈpɛɹəˌɫæks/ (US) · /pˈæɹəlˌæks/ (UK)

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

## Senses

### 1. apparent shift in position

noun · CEFR C1 · Technical

the way an object seems to move when you look at it from a different place.

For teachers: the apparent displacement of an observed object due to a change in the position of the observer.

- If you hold your finger in front of your face and close one eye, then the other, the finger's position changes because of parallax.
- The photographer had to adjust for parallax error because the viewfinder was slightly offset from the camera's actual lens.

### 2. astronomical measurement

noun · CEFR C2 · Technical

a method used by astronomers to calculate the distance to stars by looking at them from different sides of the Earth's orbit.

For teachers: the angle used to determine the distance of celestial bodies, specifically the semi-angle of the maximum parallax created by the Earth's orbit.

- Astronomers use stellar parallax to measure the distance of stars that are relatively close to our solar system.
- By measuring the tiny shift in a star's position relative to distant galaxies over six months, researchers can calculate its distance via annual parallax.

### 3. to shift layers at different speeds

verb · CEFR C1 · Technical

to move different parts of a digital image at different speeds to make it look 3D.

For teachers: to produce an illusion of depth in computer graphics by moving background layers slower than foreground layers.

- The video game uses a parallax effect to make the mountains in the background look very far away.
- The web designer implemented a parallax scrolling effect to create a more immersive and three-dimensional experience for mobile users.

## Examples

- Astronomers use parallax to measure the distance to nearby stars.
- By observing the same star from opposite sides of the Earth's orbit, scientists calculated its parallax to determine its exact distance.
- The measurement of stellar parallax provides a fundamental baseline for the cosmic distance ladder, allowing astronomers to calibrate the distances to more distant galaxies.

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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.