- Chemistry. a substance that causes or accelerates a chemical reaction without itself being affected.
- something that causes activity between two or more persons or forces without itself being affected.
- a person or thing that precipitates an event or change: His imprisonment by the government served as the catalyst that helped transform social unrest into revolution.
- a person whose talk, enthusiasm, or energy causes others to be more friendly, enthusiastic, or energetic.
- a substance that increases the rate of a chemical reaction without itself suffering any permanent chemical changeCompare inhibitor (def. 2)
- a person or thing that causes a change
“substance which speeds a chemical reaction but itself remains unchanged,” 1902, formed in English (on analogy of analyst) from catalysis. Figurative use by 1943.
- A substance, usually used in small amounts relative to the reactants, that modifies and increases the rate of a reaction without being consumed in the process.
- A substance that starts or speeds up a chemical reaction while undergoing no permanent change itself. The enzymes in saliva, for example, are catalysts in digestion.