catalyst

noun

cat·​a·​lyst ˈka-tə-ləst 

1

: a person or thing that provokes or speeds significant change or action

a catalyst for economic growth

the catalyst behind the decision

Look at passionate young people from any era and you'll find impressive catalysts for change.

—Erin Blakemore

2

: a substance that enables a chemical reaction to proceed at a usually faster rate or under different conditions (as at a lower temperature) than otherwise possible

Depending on the catalyst used, the device either splits water to make hydrogen fuel or splits water and CO₂ to create syngas …

—Prachi Patel

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Word History of Catalyst

Catalyst is a fairly recent addition to the English language, first appearing at the start of the 20^th century with its chemistry meaning. It was formed from the word catalysis, another chemistry term which refers to a modification and especially an increase in the rate of a chemical reaction induced by material unchanged chemically at the end of the reaction. By the 1940s, the figurative sense of catalyst was in use for someone or something that quickly causes change or action.

Examples of catalyst in a Sentence

The bombing attack was the catalyst for war.

She was proud to be a catalyst for reform in the government.

Recent Examples on the Web

Instead, the plan is for NASA astronauts to help establish a permanent lunar settlement on the moon's unexplored south pole that would be a catalyst in making future human missions from the moon to Mars possible. —Eric Lagatta, USA Today, 31 Oct. 2025

This final step uses cobalt molybdenum as the most effective catalyst to refine the oil into pure hydrocarbons that meet jet fuel specifications. —Mrigakshi Dixit, Interesting Engineering, 30 Oct. 2025

While the drug did come up slightly short of expectations, the real test, and next major catalyst for the stock, will be its trial data for Alzheimer's psychosis. —Zev Fima, CNBC, 30 Oct. 2025

Each foundation must define its mission, yet there is real potential for philanthropy to act as a catalyst for creative financing. —Anna Broughel, Forbes.com, 29 Oct. 2025

Word History

Etymology

see catalysis

First Known Use

1902, in the meaning defined at sense 2

Phrases Containing catalyst

• co-catalyst

Rhymes for catalyst

• catalysed

Kids Definition

catalyst

noun

cat·​a·​lyst ˈkat-ᵊl-əst 

1

: a substance that changes the rate of a chemical reaction but is itself unchanged at the end of the process

especially : such a substance that speeds up a reaction or enables it to proceed under milder conditions

2

: a person or event that quickly causes change or action

the scandal was a catalyst for reform

Medical Definition

catalyst

noun

cat·​a·​lyst ˈkat-ᵊl-əst 

: a substance (as an enzyme) that enables a chemical reaction to proceed at a usually faster rate or under different conditions (as at a lower temperature) than otherwise possible