| a. | 1. | (Opt.) Pertaining to, or possessing the properties of, a species of caustic curves formed by refraction. See Caustic surface, under Caustic. |
| n. | 1. | (Med.) That which burns by refraction, as a double convex lens, or the sun's rays concentrated by such a lens, sometimes used as a cautery. |
| 2. | (Math.) A curved formed by the consecutive intersections of rays of light refracted through a lens. |