あかり Akari. light; illumination
The Akari Day Committee's official site identifies October 21 as あかりの日, created by three lighting organizations and tied to Edison's practical incandescent lamp experiment of October 21, 1879.
Why this date: October 21 is the official annual date of あかりの日.
Language note: あかり (akari) means light or illumination, especially light as experienced in a place. The all-hiragana form feels warm and accessible.
Good lighting does more than brighten a room; it shapes how the room feels.
DJW practice example: 必要な場所に、やさしいあかりを灯す。 Hitsuyō na basho ni, yasashii akari o tomosu. Light a gentle lamp where it is needed.
Sources: Akari Day Committee — あかりの日: https://www.akarinohi.jp/