optical illusion
optical illusion — noun
1. Something you see whose appearance your eyes and brain interpret in a way that d
Something you see whose appearance your eyes and brain interpret in a way that does not match the actual object, such as a shape that seems to bend or a colour that seems to shift.
The two lines looked like different lengths, but it was just an optical illusion.
countable: an optical illusion
Wei stared at a spiral pattern — the moving edges were an optical illusion.
A museum room has optical illusions where visitors appear to shrink or grow.
In the Hermann grid illusion, grey dots seem to appear where the white lines cross.
A grey square on yellow looks blue — a simple optical illusion of colour contrast.
- visual trick
less formal, used in everyday conversation
- trick of the eye
idiomatic and informal
- visual illusion
more technical, used in psychology
文法句型
[countable] an optical illusion
there is/are + an optical illusion
用法筆記
An optical illusion is a normal trick of vision — it happens to everyone. It is NOT the same as a hallucination, which is caused by illness or drugs and has no real external object.
常見錯誤
2. A picture or drawing that is designed to confuse the eye, so that you see someth
A picture or drawing that is designed to confuse the eye, so that you see something impossible, two different things in the same image, or a shape that seems to move or change.
This famous optical illusion shows a young woman and an old lady in one drawing.
pattern: shows both X and Y in the same drawing
Diego looked at a cube optical illusion that seemed to flip direction every few seconds.
The duck-rabbit illusion lets you see a bird or a rabbit in the same outline.
The Penrose triangle is an optical illusion — an impossible object whose corners look connected.
- visual puzzle
emphasises the puzzle-like quality
- trick drawing
informal, used for deliberately created images
文法句型
[countable] an optical illusion of [noun]
用法筆記
This sense refers specifically to images deliberately designed as visual puzzles — for example, ambiguous figures (duck/rabbit, young woman/old lady) and impossible objects (Penrose triangle). Distinguish from sense 1 (which covers any visual trick, including natural ones like after-images) and from sense 3 (which covers misperceptions of real scenes caused by natural conditions).
3. A situation in which you misjudge a real object or scene because of the way ligh
A situation in which you misjudge a real object or scene because of the way light, shadows, perspective, or surrounding shapes affect your vision — for example, thinking a straight stick in water is bent.
Water bends light, making a pencil in a glass look bent — an optical illusion.
pattern: an optical illusion caused by [natural phenomenon]
Dr. Okafor said the huge moon near the horizon is an optical illusion of distance.
Railway tracks seem to meet in the distance — an optical illusion, but stay parallel.
Desert hikers sometimes mistake hot air for water — an optical illusion from warm air.
- visual misperception
technical, used in psychology and optics
- perceptual error
formal, describes the cognitive process rather than the image
文法句型
[countable] an optical illusion caused by [noun]