Definition of catalyst in English:


Line breaks: cata|lyst
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
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    • 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
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    • 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.

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