oˈvernight noun

1. A stay lasting one night
2. The evening just past (Shakespeare; now chiefly US)

To spend the night

1. For the duration of the night, until the next morning during the night
2. In the course of the night
3. Hence, extraordinarily quickly
4. On the evening of the day just past

1. Done or occurring or existing overnight
2. Sudden
3. For the time from evening until next morning (overnight bag or case a small case for carrying the clothes, toilet articles, etc, needed for an overnight stay)