noun
The general physical phenomenon of light, as opposed to darkness or sound.
光がないと植物は育たない。
Plants do not grow without light.
光の速さは音よりずっと速い。
The speed of light is much faster than the speed of sound.
noun
illumination; ray; beam; glow
Used for visible light coming from a source or appearing as a ray, beam, gleam, or glow.
雲の間から一筋の光が差し込んだ。
A single beam of light shone through the clouds.
遠くに町の光が見えた。
We could see the glow of the town in the distance.
noun
hope; happiness; bright prospect
Figurative use: something that gives emotional brightness, hope, or a reason to keep going.
長い闘病生活の中で、家族の励ましが光になった。
During the long illness, his family's encouragement became a source of hope.
noun
Rare or old-fashioned as an independent sense; most recognizable in fixed or proverbial expressions where 光 suggests the power or prestige someone casts around them.
「親の光は七光り」という古いことわざで、光は親の権勢や影響力を指す。
In the old saying 親の光は七光り, 光 refers to a parent's prestige or influence.
noun
Literary or euphemistic use, especially in phrases such as 光を失う, meaning to lose one's sight.
彼は目の病気で光を失った。
He lost his sight because of an eye disease.
noun
optical fiber; fiber-optic internet
Abbreviation of 光回線 or 光ファイバー in Internet and telecommunications contexts.
See also: 光回線
引っ越しを機に、ネットを光にした。
When I moved, I switched my internet connection to fiber-optic.