Refract

rē-frakt′, v.t. to break back or open: to break the natural course, or bend from a direct line, as rays of light, .— adj. Rēfrac′table .— p.adjs . Rēfrac′ted , turned out of its straight course, as a ray of light: ( bot. , .) bent back at an acute angle; Rēfrac′ting , serving or tending to refract: refractive.— n. Rēfrac′tion , the act of refracting: the change in the direction of a ray of light, heat, ., when it enters a different medium.— adj. Rēfrac′tive , refracting: pertaining to refraction.— ns. Rēfrac′tivene ; Rēfractiv′ity ; Rēfractom′eter , an instrument for measuring the refractive power of different substances; Rēfrac′tor , a refracting telescope.— Angle of refraction , the angle between a perpendicular and a ray of light after its change of direction, bearing a constant ratio to the sine of the angle of incidence —the index of refraction; Astronomical , or Atmospheric , refraction , the apparent angular elevation of the heavenly bodies above their true places, caused by the refraction of the rays of light in their pa age through the earth's atmosphere; Double refraction , the separation of an incident ray of light into two refracted rays, polarised in perpendicular planes. [L. refringĕre , refractum — re- , back, frangĕre , to break.]