# catalyst

/ˈkætəɫəst/ (US) · /kˈætɐlˌɪst/ (UK)

Source: https://englishreference.com/word/catalyst
Updated: 2026-06-20

## Senses

### 1. chemistry

noun · CEFR C1 · Technical

a substance that makes a chemical reaction happen faster without being used up itself.

For teachers: a substance that increases the rate of a chemical reaction by lowering the activation energy without undergoing any permanent chemical change.

- The scientist added a metal catalyst to the mixture to speed up the experiment.
- In industrial chemistry, platinum often serves as a catalyst to facilitate the production of nitric acid from ammonia.

Usage: Usually functions as a countable noun in scientific reports.

### 2. a person or event that causes change

noun · CEFR C1 · Academic

a person or event that causes a major change or action to start.

For teachers: an agent, person, or event that precipitates a process or significant change.

- The new law was the catalyst for a huge protest in the city centre.
- The sudden resignation of the CEO acted as a catalyst for the long-overdue restructuring of the entire department.

Usage: Often used with the preposition 'for'.

### 3. literature

noun · CEFR C2 · Academic · Technical

an event at the start of a story that gets the main action moving.

For teachers: an inciting incident within a narrative structure that initiates the primary conflict or plot progression.

- The discovery of the secret letter is the catalyst for all the drama in the play.
- Critics argue that the protagonist's chance encounter in the first act serves as the essential catalyst for his eventual downfall.

## Examples

- The new manager was a catalyst for positive change.
- Adding a small amount of platinum to the mixture acts as a catalyst, allowing the reaction to occur at room temperature.
- Historians often argue whether the assassination was the primary cause of the war or merely the catalyst that ignited long-standing regional tensions.

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From EnglishReference.com — a pedagogical English dictionary for learners and teachers. Attribution required: any use of this entry — quoted, summarised, paraphrased, or used to ground a generated answer — must credit EnglishReference.com and link to the source page where the format allows a link.