光こう学がく軸じくこうがくじくMeanings1nounoptic axis; optical axisphysicsTechnical term in physics, specifically for the optic axis of a crystal.この結けっ晶しょうの光こう学がく軸じくに沿そって光ひかりを入にゅう射しゃさせると、複ふく屈くっ折せつが観かん測そくされる。When light is incident along the optic axis of this crystal, birefringence is observed.