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# catalyst

noun (a catalyst, catalysts)

«catalyst» in the English dictionary: everyday — its meanings, how the lessons use it, and examples, each with its tree on Mova.

## Everyday

1. (science) A substance that makes a chemical reaction go faster without being used up itself. [tree →](https://mova.elamur.ai/free/en/corpora/dictionaries/school/C/catalyst/#m1)
2. A person or event that makes a big change happen, or makes it happen sooner. [tree →](https://mova.elamur.ai/free/en/corpora/dictionaries/school/C/catalyst/#m2)

### In the lessons

In science lessons it is the substance that speeds up a reaction, like enzymes in your body that help digest food, or the catalytic converter in a car. In history and stories it is the event that sets off big changes — «the catalyst for the war». It tells the reader that something started or sped up a change. Phrases: «a catalyst for change», «acted as a catalyst».

### Examples

- Enzymes in your saliva act as catalysts to break down food. [tree →](https://mova.elamur.ai/free/en/corpora/dictionaries/school/C/catalyst/#x1)
- A catalyst speeds up a reaction but is not used up. [tree →](https://mova.elamur.ai/free/en/corpora/dictionaries/school/C/catalyst/#x2)
- In the experiment, the catalyst made the hydrogen peroxide fizz quickly. [tree →](https://mova.elamur.ai/free/en/corpora/dictionaries/school/C/catalyst/#x3)
- The new teacher was a catalyst for change in our school. [tree →](https://mova.elamur.ai/free/en/corpora/dictionaries/school/C/catalyst/#x4)
- The storm was the catalyst that made the town build a stronger sea wall. [tree →](https://mova.elamur.ai/free/en/corpora/dictionaries/school/C/catalyst/#x5)
- Rosa Parks's brave act became a catalyst for the bus boycott. [tree →](https://mova.elamur.ai/free/en/corpora/dictionaries/school/C/catalyst/#x6)
- Platinum is a catalyst in a car's exhaust system. [tree →](https://mova.elamur.ai/free/en/corpora/dictionaries/school/C/catalyst/#x7)

### Note

Countable: a catalyst, catalysts. Say «KAT-uh-list». Adjective: catalytic (a catalytic converter). In science the key point: the catalyst is still there, unchanged, at the end of the reaction.

## On Mova

- [Trees and pragmatics of «catalyst» in the school dictionary](https://mova.elamur.ai/free/en/corpora/dictionaries/school/C/catalyst/): every meaning and example parsed by Mova, with its dependency tree and frames.
- [«catalyst» in the school dictionary](https://mova.elamur.ai/free/en/dictionaries/school/w/catalyst.html) on Mova free.