refractio

refractio [ML < CL refractus p. ppl. of refringere+-tio] 1 (act of) bending or deflecting the course of (a ray of light), refraction; b (in fig. context). inquirere ‥ annon fiat iris per radios incidentes vel per reflexionem vel per ~onem Bacon Maj. II 185; secunda visio est per ~onem Wycl. Dom. Div. 187 (v. refringere 3).  b s1422 si in speculo interne consideracionis teipsum tibi objectum statueres, animadverteresque debite et absque radiorum ~one Amund. I 92. 2 (act of) turning back the course of (a beam of light), reflection, or ? f. l. experimenta ‥ quibus cognovimus quod ~o [v. l. reflexio] radii super speculum fit in angulo equali angulo incidentie Gros. 75.