noun
source of light; light source
Refers to something that emits light, such as a lamp, candle, or the sun. Used in both literal and figurative contexts.
部屋の明り先は小さなランプだけだった。
The only source of light in the room was a small lamp.
彼女は私の人生の明り先だ。
She is the light of my life.
光源 is a more technical term for 'light source', often used in physics or engineering, while 明り先 is a more poetic or everyday word.
Compound of 明り (akari, 'light') and 先 (saki, 'source' or 'destination'). The exact historical derivation is uncertain, but the word is conventionally associated with the idea of where light comes from.