Webster's Revised Unabridged Dictionary · 1913

Overnight

Overnight , noun

The fore part of the night last past; the previous evening. [Rare] — Shakespeare

overnight , adverb

1.
In the fore part of the night last past; in the evening before.
2.
Throughout the night; as, the candle will not last overnight.
3.
During the night; hence, in a short period of time; as, his prospects of winning changed overnight.
I had been telling her all that happened overnight. — Dickens

overnight , adjective

Occurring or accomplished during one night; as, guaranteed overnight delivery of a package.