Diacaustic

Part of speech: noun (n.)

1. 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. A curved formed by the consecutive intersections of rays of light refracted through a lens.

Part of speech: adjective (a.)

Pertaining to, or possessing the properties of, a species of caustic curves formed by refraction. See Caustic surface, under Caustic.