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noun

refraction

ri-FRAK-shuhn

Refraction (noun) means the bending of light, sound or water waves as they pass from one material into another in which they travel at a different speed. Example: “Refraction is why a straw looks broken where it enters a glass of water.”

noun
1
The bending of light, sound or water waves as they pass from one material into another in which they travel at a different speed.
"Refraction is why a straw looks broken where it enters a glass of water."
"The rainbow forms through the refraction and reflection of sunlight inside raindrops."
2
medical An eye test that measures how the eye bends light, used to work out the strength of lens a person needs.
"The optician performed a refraction before writing the prescription."

How to Use Refraction

Learner’s notes

In plain EnglishLight bending as it passes from one thing into another, like air into water.

When to use it

Neutral and technical; standard in physics, optics and optometry.

Memory tip

The related adjective is refractive, as in refractive index and refractive error.

Trace the full origin ↓
Easily confused with
Common pairings
index of refraction angle of refraction atmospheric refraction refraction test
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Fill the Gap

Can you complete this real example?

_____ is why a straw looks broken where it enters a glass of water.

Etymology

From Latin refractus, past participle of refringere "to break up", from re- "back" and frangere "to break".

Origin: Latin

Related Words

Rhymes for refraction

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Frequently Asked Questions

What is the difference between refraction and reflection?

Reflection is light bouncing off a surface and travelling back into the same material, which is how a mirror works. Refraction is light passing through into a new material and changing direction because its speed changes. A window does both at once: you see the street through it by refraction and your own faint image by reflection.

Why does refraction happen?

Light travels at different speeds in different materials, so when a wave enters a new material at an angle, one side of the wave front slows down before the other. That uneven slowing swings the wave onto a new path.

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Definitions: FreeDict original editorial · etymology from FreeDict original editorial