How to say "brightness" in Japanese

• 輝きかがやきCommon
  nounBrightness as a visible, shining quality — the radiance or brilliance of stars, jewels, eyes, or a smile. Use this for the shine you actually see, whether literal or figurative.
  おまえの全すべてが俺おれの中なかで輝かがやきを放はなち続つづける。↗

  All of you in my memory is still shining in my heart.
• 輝度きどCommon
  nounBrightness as a measurable physical quantity — luminance in optics and display technology. This is the scientific term; for the shine you see with your eyes, 輝き is the word.
• 光輝こうきCommon
  nounBrightness as splendor: grand, glorious radiance, as of the sun or gold. It conveys brilliance that dazzles or inspires, rather than a measured value or the plain shine of things.

For visible or figurative shine choose 「輝き」; for brightness as a measured physical quantity (luminance, screen brightness) choose 輝度; for brightness as grand, glorious splendor choose 光輝.

Usage comparisons are AI-assisted and cross-checked by multiple models; for study reference only

• 輝きかがやきbrightness
• 輝度きどbrightness
• 光輝こうきbrightness
• 明度めいどbrightness
• 明るさあかるさbrightness
• 融朗ゆうろうbrightness
• ブライトネスbrightness
• 明めいbrightness