SIT UP


Meaning of SIT UP in English

1.

to be or move yourself into a sitting position, rather than lying down or leaning back :

Sit up straight—don't slouch.

2.

to not go to bed until later than usual :

We sat up half the night, talking.

Oxford Advanced Learner's English Dictionary.      Оксфордский английский словарь для изучающик язык на продвинутом уровне.