catalyst

catalyst — noun

1. in chemistry, any material that quickens the speed of a reactive process while r

1.nounB2
Definition

in chemistry, any material that quickens the speed of a reactive process while remaining chemically unchanged itself — for instance, the enzymes in your mouth break down food far more quickly than would happen on their own.

Example

Platinum is often used as a catalyst in car exhaust systems to remove harmful gases.

catalyst in [system] for speeding reactions

Without the right catalyst, the two liquids would sit in the flask without reacting at all.

Common collocations
  • act as a catalyst
  • serve as a catalyst
  • catalyst for [reaction]
  • catalyst in [process]
  • metal catalyst
  • biological catalyst
Synonyms
  • enzyme

    a specific biological catalyst found in living organisms; narrower than catalyst

  • accelerant

    a substance that speeds a chemical process; less common in formal chemistry writing

  • agent

    a broader term for something that produces an effect; less specific to speeding reactions

Antonyms
  • inhibitor

    a substance that slows down or stops a chemical reaction

Grammar Patterns

catalyst for [process]

catalyst in [reaction]

Usage Note

In chemistry, the noun is often paired with a specific metal or compound name ("an iron catalyst", "a palladium catalyst"). Common collocations include "act as a catalyst", "serve as a catalyst", and "catalyst for [a specific reaction]".

Common Mistakes

The heat was a catalyst for boiling the water.
The heat was the energy source for boiling the water.
Boiling is a physical change, not a chemical reaction, so 'catalyst' does not apply here.

2. an event, a person, or an action that drives a major shift or transformation to

2.nounB2
Definition

an event, a person, or an action that drives a major shift or transformation to unfold more rapidly or with greater intensity than would otherwise occur — for example, a protest that leads to new laws, or a leader whose arrival sparks reform within a company.

Example

The earthquake became a catalyst for rebuilding the city's old and unsafe infrastructure.

catalyst for [positive/negative outcome] — event as trigger

Aiko's passionate speech was the catalyst that pushed the student council to demand better cafeteria food.

Common collocations
  • catalyst for change
  • catalyst for reform
  • act as a catalyst
  • serve as a catalyst
  • catalyst of transformation
Synonyms
  • trigger

    an event that sets something in motion; suggests a more immediate cause than catalyst

  • spark

    a small event that starts a much larger development; more dramatic than catalyst

  • impetus

    a force that encourages something to happen; more abstract and formal

  • stimulus

    something that encourages activity or growth; broader in application

Antonyms
  • obstacle

    something that blocks or slows change rather than accelerating it

  • deterrent

    a factor that discourages action or change from happening

Grammar Patterns

catalyst for [change]

catalyst of [transformation]

Usage Note

In figurative use, the noun is commonly followed by 'for' or 'of' ("a catalyst for change", "a catalyst of reform"). The person or event is not necessarily the direct cause; rather, it triggers or accelerates a process that was already under way.

Common Mistakes

Ravi was the catalyst who cooked dinner.
Ravi was the catalyst who got the team to finally address the budget problem.
'Catalyst' implies triggering significant change or action, not just doing an ordinary task.

Word family

  • catalyze
    verbC1
  • catalytic
    adjectiveB2
  • catalysis
    nounC1

Synonym discussion

Sense: noun/2

All four words describe something that causes or accelerates change, but they differ in immediacy and scope. A 'trigger' suggests a direct, almost mechanical cause-and-effect relationship: pulling the trigger fires the gun. A 'spark' emphasizes a small initial event that ignites a much larger development — like a single match starting a forest fire. 'Impetus' is more abstract and formal, referring to a motivating force that pushes a process forward (e.g., "The new funding gave impetus to the research"). 'Stimulus' is broadest, covering anything that encourages activity or growth, from economic measures to sensory input. 'Catalyst' differs from all four because it implies accelerating an existing process rather than starting from nothing — the reaction was already possible, but the catalyst made it happen faster.

trigger ↗spark ↗impetus ↗stimulus ↗

Common collocations

Nouns

Adverbs

Phrases

  • act as a catalyst
  • serve as a catalyst
  • catalyst for change

Prepositions

Etymology

GreekNeo-LatinEnglish

The word 'catalyst' comes from the Greek 'katalysis', meaning 'dissolution' or 'breaking down' (from 'kata-' = down + 'lyein' = to loosen). The modern chemistry sense was coined in 1836 by the Swedish chemist Jöns Jakob Berzelius to describe substances that help other substances react without changing themselves. The figurative meaning — a person or event that causes major change — appeared in English in the early 1900s.