D defs.my
Entry 3 senses Webster, 1913

catalyst

· IPA /ˈkæt.ə.lɪst/
01 n. a substance that initiates or accelerates a chemical reaction without itself being affected; as, thousands of enzymes serve in concert as c…
  1. 1.
    a substance that initiates or accelerates a chemical reaction without itself being affected; as, thousands of enzymes serve in concert as calaysts to produce the sequence of reactions we call “life”; the industrial production of cheap ammonia depended on finding a good catalyst.(Chem.)
  2. 2.
    something that serves as a precipitating occasion for an event; as, the invasion acted as a catalyst to unite the country.
  3. 3.
    something or someone that causes events to happen with itself being changed.