Definition of catalyst in English:

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Pronunciation: /ˈkat(ə)lɪst/


1A substance that increases the rate of a chemical reaction without itself undergoing any permanent chemical change: chlorine acts as a catalyst promoting the breakdown of ozone
More example sentences
  • The key tools will be new breeds of enzymes - protein catalysts that speed up chemical reactions in cells.
  • Most converters use platinum or palladium metal catalysts that convert carbon monoxide and hydrocarbons to carbon dioxide and water vapor.
  • Heterogeneous catalysts are materials that increase the rate of a reaction, but are not in the same phase as the reactants.
1.1A person or thing that precipitates an event: the prime minister’s speech acted as a catalyst for debate
More example sentences
  • Though the film is around these two men, it is the women who play the catalyst to all the events and add momentum to the story.
  • It is the union of the latter two that provides the catalyst for the events that follow.
  • In Scotland, it has always been Catholic schools which have been the catalyst for this debate.


Early 20th century: from catalysis, on the pattern of analyst.

Words that rhyme with catalyst

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