To bend sharply and abruptly back; to break off. [1913 Webster]
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. [1913 Webster]
, v.tr.
1 (of water, air, glass, etc.) deflect (a ray of light etc.) at a certain angle when it enters obliquely from another medium.
2 determine the refractive condition of (the eye).