Light: something that makes objects or spaces visible or bright (natural or artificial light such as sunlight or lamps).
朝の光が窓から差し込んだ。
The morning light streamed in through the window.
部屋の光が暗いので電気をつけた。
The room was dim, so I turned on the light.
光の当たり方で絵の印象が変わる。
The impression of a painting changes depending on how the light hits it.
Illumination, ray, beam, gleam, or glow — refers to a directed or visible beam or glow of light.
夕日に照らされて、川面に光がきらめいた。
Bathed in the evening sun, the river's surface glimmered with light.
ステージのスポットライトの光が彼女を照らした。
The spotlight illuminated her on the stage.
薄い霧の中に光がぼんやりと見えた。
A faint light was visible in the thin fog.
Figuratively, light as a symbol of happiness or hope — used to describe someone or something that brings hope or joy.
子どもたちは彼女にとっての光だ。
The children are a light (source of joy/hope) to her.
震災の後、ボランティアの活動が被災地に光をもたらした。
After the disaster, volunteer efforts brought hope to the affected areas.
Figuratively, 'light' as influence, power, or prestige — used to indicate someone's influence or the prestige they confer (somewhat literary).
名誉ある賞は大学に新たな光を与えた。
The prestigious award brought new prestige (influence) to the university.
彼の成功は故郷に光を投げかけた（文語的表現）。
His success cast prestige and hope upon his hometown (literary expression).
Used sometimes to mean vision or eyesight (a somewhat archaic usage), referring to the ability to see or the field of vision.
高齢になると光が弱くなると感じる人が多い（比喩的/やや古い言い方）。
Many people feel their vision weakens as they age (figurative/somewhat old-fashioned expression).
夜道は光が頼りだ。
On a path at night, light is what you rely on (for seeing).
An abbreviation for optical fiber connection (光回線); in everyday speech, people may shorten '光回線' to just '光' when talking about internet lines.
自宅のインターネットを光に切り替えた。
I switched my home internet to an optical fiber connection.