catalyst
[noun]
Synonyms: stimulus, goad, impetus, impulse, incentive, incitation, incitement, motivation, spur, stimulant

[TahlilGaran] English Synonym Dictionary ▲

cat‧a‧lyst /ˈkætl-əst, ˈkætl-ɪst/ noun [countable]
[Date: 1900-2000; Origin: catalysis, on the model of analyst]

1. technical a substance that makes a chemical reaction happen more quickly without being changed itself

2. something or someone that causes an important change or event to happen
catalyst for
They hope his election will act as a catalyst for reform.
—catalytic /ˌkætlˈɪtɪk◂/ adjective

[TahlilGaran] Dictionary of Contemporary English ▲