Definition
In chemistry, a catalyst speeds up a reaction while remaining unconsumed: it leaves the flask exactly as it entered. The figurative sense keeps that beautiful asymmetry — a catalyst for change is the small event, person, or idea that sets everything else in motion while itself staying what it was. A protest becomes the catalyst for reform; a chance meeting becomes the catalyst for a career. The change is enormous; the cause is, somehow, untouched.
Examples
- The fuel crisis acted as a catalyst for serious investment in public transport.
- In the experiment, platinum serves as a catalyst and is not used up in the reaction.
- Her year abroad was the catalyst that changed how she thought about home.
Synonyms
spark · stimulus · trigger · impetus · spur
In TOEFL & IELTS
Lives a double life in the exams: TOEFL chemistry lectures use the literal sense, while history and sociology passages use 'a catalyst for change/reform/growth' — one of the highest-value collocations you can deploy in IELTS Writing Task 2. The verb is 'catalyze'; the adjective 'catalytic' survives mostly in 'catalytic converter'.