catalyst

1. (chemistry) A substance that increases the rate of a chemical reaction without being consumed in the process.Examples: "Enzymes, the catalysts of biological systems, are remarkable molecular devices that determine the pattern of chemical transformations."

2. (figurative) Something that encourages progress or change.Examples: "Economic development and integration are working as a catalyst for peace."; "It was a morning baptized by my first cup of coffee, freshly brewed over a gravel-bar fire, while they celebrated with the stronger catalyst of sour-mash whiskey in their fishing-vest cups."; "Israel's fear for the reactor—rather than Egypt's of it—was the greater catalyst for war."Synonyms: stimulus, straw that stirs the drinkAntonyms: inhibitor, dampenerfiguratively

3. (literature) An inciting incident that sets the successive conflict into motion.Examples: "The current view by both Labour and Conservative politicians is that the state of the UK railway is unsustainable, and the pandemic acted as a catalyst in exposing its weaknesses."

4. (automotive) A catalytic converter.

5. (fantasy) An object that facilitates the casting of a spell (such as a magic wand).