Diacaustic

Definition:

(a.) Pertaining to, or possessing the properties of, a species of caustic curves formed by refraction. See Caustic surface, under Caustic.
(n.) 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.
(n.) A curved formed by the consecutive intersections of rays of light refracted through a lens.

Compare diacaustic with other words:

diacaustic vs. diacoustic