Source : Webster's Revised Unabridged Dictionary (1913)

Refract \Re*fract"\ (r?*fr$kt"), v. t. [imp. & p. p.
   {Refracted}; p. pr. & vb. n. {Refracting}.] [L. refractus, p.
   p. of refringere; pref. re- re- + frangere to break: cf. F.
   r['e]fracter. SEe {FRacture}, and cf. {Refrain}, n.]
   1. To bend sharply and abruptly back; to break off.

   2. To break the natural course of, as rays of light orr heat,
      when passing from one transparent medium to another of
      different density; to cause to deviate from a direct
      course by an action distinct from reflection; as, a dense
      medium refrcts the rays of light as they pass into it from
      a rare medium.

Source : WordNet®

refract
     v 1: subject to refraction; "refract a light beam"
     2: determine the refracting power of (a lens)