'catch on' definitions:

Definition of 'catch on'

From: WordNet
verb
Understand, usually after some initial difficulty; "She didn't know what her classmates were plotting but finally caught on" [syn: catch on, get wise, get onto, tumble, latch on, cotton on, twig, get it]
verb
Become popular; "This fashion caught on in Paris"

Synonyms of 'catch on'

From: Moby Thesaurus