also: ちっこう
noun
phosphorescence; luminescence
Refers to materials that absorb light and then emit it slowly, often used in glow-in-the-dark products. Compare 夜光 (やこう), which can refer to any light emission at night, not necessarily from stored energy.
See also: 夜光
この時計の文字盤には蓄光塗料が使われている。
The dial of this watch uses phosphorescent paint.
蓄光素材は光を蓄えて暗闇で光る。
Phosphorescent materials store light and glow in the dark.
夜光 broadly means 'nocturnal light' or 'glow at night' and does not necessarily imply energy storage; 蓄光 specifically refers to phosphorescence where light is absorbed and re-emitted.
Compound of 蓄 (store, accumulate) and 光 (light), literally 'stored light'. The term is a modern technical coinage for phosphorescent materials.