What does “catch up with something” mean?
To "catch up" with something means to get to something or someone. Harry and Ron said that they need to catch up to the train. They want to meet up with the train; to get to the train. Here are a couple of examples: They tried to catch up to the car ahead of them. He is so fast! I couldn't catch up with him. "Catch up" can also mean to visit and talk with someone that you haven't seen in awhile. Ex: We need to catch up! I haven't seen you in so long! It's so great to catch up with you. It's really nice to see you again.