Real Dictionary

catch up
phrasal verb: If you are caught up in something, you are involved in it, usually unwillingly.
phrasal verb: If you catch up on an activity that you have not had much time to do recently, you spend time doing it.
phrasal verb: If you catch up on friends who you have not seen for some time or on their lives, you talk to them and find out what has happened in their lives since you last talked together.
phrasal verb: If you catch up with someone who is in front of you, you reach them by walking faster than they are walking.
phrasal verb: To catch up with someone means to reach the same standard, stage, or level that they have reached.

catch up in American English
to lift or snatch suddenly
to take or lift up suddenly; seize; snatch

catch up in British English
to seize and take up (something) quickly
noun: an act or instance of making up for lost ground or dealing with a backlog

catch-up in American English
of or having to do with catching up
adjective: intended to keep up with or surpass a norm or competitor
noun: an effort to reach or pass a norm, esp. after a period of delay