subs. phr. (colloquial).The first three or four hours after midnight: usually THE SMALL HOURS of the morning. Also SHORT HOURS.
1787. BURNS, Death and Doctor Hornbook. Some wee SHORT HOUR ayont the twal.
1903. Daily Telegraph, 3 Jan., 9, Paris Day by Day. An extraordinary assault has been committed in a third-class carriage of a train which left Paris in the SMALL HOURS of yesterday morning for Brussels.