caustic curve

(optics) A curve to which the ray of light, reflected or refracted by another curve, are tangents, the reflecting or refracting curve and the luminous point being in one plane.

Japanese Meaning

光学において、ある曲線により反射または屈折した光線が接線となる軌跡。反射または屈折する曲線と発光点が同じ平面上にある点が特徴となる。

What is this buttons?

Google Translation / DeepL Translation

点光源が反射面を照らすと、反射や屈折によって生じる光線の包絡線が床に明るい三日月形を描く。

Details

Sense（1）

(optics) A curve to which the ray of light, reflected or refracted by another curve, are tangents, the reflecting or refracting curve and the luminous point being in one plane.