noun a curved formed by the consecutive intersections of rays of light refracted through a lens.
2. diacaustic ·noun 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.
3. diacaustic ·adj pertaining to, or possessing the properties of, a species of caustic curves formed by refraction. ·see caustic surface, under caustic.