sit up

Meanings

1. To assume a sitting position from a position lying down.
2. To sit erect.
3. To show sudden interest or surprise.
4. To bounce, especially to a comfortable height.
5. To not go to bed (notionally remaining in a sitting position).
6. For a young lady to open her house for several successive nights for any visitors who wish to pay their respects.

1. Alternative spelling of sit-up.

Etymology

From Middle English upsitten (“to sit up”).