Literary or formal word for dawn; in everyday speech 夜明け is more common.
We set out at daybreak.
Tenmei era (1781–1789)
Historical Japanese era name; used in dates and historical contexts.
The Great Tenmei Famine was a major disaster of the Edo period.
Tenmei famine (1782-1787)
From Middle Chinese 天明 (then mjieng). The era name sense is a specific historical usage.