1.
to spend extra time doing sth because you have not done it earlier :
I have a lot of work to catch up on.
2.
to find out about things that have happened :
We spent the evening catching up on each other's news.
1.
to spend extra time doing sth because you have not done it earlier :
I have a lot of work to catch up on.
2.
to find out about things that have happened :
We spent the evening catching up on each other's news.
Oxford Advanced Learner's English Dictionary. Оксфордский английский словарь для изучающик язык на продвинутом уровне. 2005