catalyst
https://gyazo.com/454d26f0e5a3f98212ccb8c55e4ee7ac
source: Definition of catalyst - Chemistry Dictionary
noun
a substance that increases the rate of a chemical reaction without itself undergoing any permanent chemical change.
〘化〙 触媒
a person or thing that precipitates an event:
«…の» 変化を促すもの[人], 要因, きっかけ «for»
e.g. the governor's speech acted as a catalyst for debate.
ORIGIN
early 20th century: from catalysis, on the pattern of analyst.