To become popular or fashionable; to start being liked or used by many people.
Electric scooters really caught on in the city last year.
A: Do you think this new app will catch on? B: Definitely. Everyone loves how easy it is to use.
In my opinion, online shopping caught on quickly because it saves people a lot of time.
Common mistake
✗The idea didn't catch up.
✓The idea didn't catch on.
'Catch on' = become popular; 'catch up' = reach the same level — different meaning.
Tell it apart
The fashion caught on quickly.
became popular
The fashion died out quickly.
fell out of use
Use 'catch on' to talk about trends, ideas, or things that more and more people start to like or use.'Catch on' (become popular) is different from 'catch up' (reach the same level) and 'catch on' (understand).
To begin to understand something, especially after not understanding at first.
It took me a while to catch on, but now I understand how the system works.
A: Did you get the joke? B: Oh, now I catch on! That was funny.
At first, I found the instructions confusing, but I caught on after watching a few videos.
Common mistake
✗She didn't catch on the joke.
✓She didn't catch on to the joke. / She didn't catch on.
'Catch on TO something', or 'catch on' alone — don't drop 'to' before the thing.
Tell it apart
He soon caught on to what we meant.
understood it
He soon caught up with the others.
reached their level
Use 'catch on' when someone finally understands an idea, joke, or situation.'Catch on' (understand) is about finally understanding, not about becoming popular.