蛍 光(けいこう)

けいこう

noun

fluorescence; fluorescent

1. fluorescence; fluorescent light

The emission of light by a substance that has absorbed light or radiation. In everyday use, most commonly refers to fluorescent lighting or fluorescent colors.

蛍光(けいこう)灯(とう)を交換(こうかん)する。

To replace the fluorescent light.

蛍光(けいこう)ペンで大事(だいじ)なところに線(せん)を引(ひ)く。

To highlight important parts with a highlighter pen.

夜(よる)の安全(あんぜん)のために、蛍光(けいこう)色(いろ)のベストを着(き)て走(はし)ることにしている。

For safety at night, I make it a point to wear a fluorescent-colored vest when running.

Refers to fluorescence — the property of emitting bright light. Composed of 蛍(けい) (firefly) + 光(こう) (light), literally "firefly light," because the glow resembles that of a firefly. Most commonly encountered in compounds related to fluorescent lighting and colors.

Common collocations

蛍光(けいこう)灯(とう): fluorescent light tube
蛍光(けいこう)ペン: highlighter pen
蛍光(けいこう)色(いろ): fluorescent color
蛍光(けいこう)塗料(とりょう): fluorescent paint
蛍光(けいこう)物質(ぶっしつ): fluorescent substance

Similar words

発光(はっこう): luminescence — the general phenomenon of emitting light
LED: LED — increasingly replacing 蛍光(けいこう)灯(とう) in Japanese households

Usage

While traditional 蛍光(けいこう)灯(とう) (fluorescent tubes) are being phased out in favor of LED lighting in Japan, the word 蛍光(けいこう) remains widely used, especially in 蛍光(けいこう)ペン (highlighter) and 蛍光(けいこう)色(いろ) (neon/fluorescent colors).

Related Words

Compare: 発光(はっこう) (luminescence)

general

Added 2026.3.30 1:24 · Revised 2026.9.4 21:31

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