refraction

UK: /rɪˈfrækʃ^ən/ US: /rɪˈfrækʃən/ ,(ri frak′shən)

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

re•frac•tion /rɪˈfrækʃən/   n. [uncountable]

1. Optics, Physics the change of direction of a ray of light in passing through different substances, as glass or water, at an angle.

re•frac•tive, adj. See -frac-.

WordReference Random House Unabridged Dictionary of American English © 2026

re•frac•tion  (ri frak′shən), n. 

1. Optics, Physics [Physics.] the change of direction of a ray of light, sound, heat, or the like, in passing obliquely from one medium into another in which its wave velocity is different.
2. Ophthalmology
   • the ability of the eye to refract light that enters it so as to form an image on the retina.
   • the determining of the refractive condition of the eye.
3. Astronomy
   • Astronomy Also called astronomical refraction. the amount, in angular measure, by which the altitude of a celestial body is increased by the refraction of its light in the earth's atmosphere, being zero at the zenith and a maximum at the horizon.
   • Astronomy the observed altered location, as seen from the earth, of another planet or the like due to diffraction by the atmosphere.

• Late Latin refrāctiōn- (stem of refrāctiō). See refract, -ion
• 1570–80

re•frac′tion•al, adj. 

Collins Concise English Dictionary © HarperCollins Publishers::

refraction / rɪˈfrækʃən/ noun

1. the change in direction of a propagating wave, such as light or sound, in passing from one medium to another in which it has a different velocity
2. the amount by which a wave is refracted
3. the ability of the eye to refract light