Overnight/ˌəʊvərˈnaɪt/ Definition 1 of 3Pro Tip 1/3Duration emphasized Emphasizes that something continues for the whole night without interruption. The baby cried overnight, so nobody got much sleep. Pro Tip 2/3Travel context Often used to describe travel plans that involve leaving in the evening and arriving the next morning. We're catching the overnight train to Scotland. Pro Tip 3/3Temporary stay Suggests a short, often one-night stay, typically for convenience. I'm staying overnight at a friend's place after the concert.