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

That ’94 tournament was a big catalyst for the game in America, helping to launch Major League Soccer in its aftermath. —Andrés Martinez, Time, 5 Dec. 2025

This man did not know me, but that moment became a catalyst. —Lizz Schumer, PEOPLE, 5 Dec. 2025

His response drew the president’s ire, which served as the catalyst for primary challenge threats and violent harassment against Indiana Republicans who opposed redistricting. —David Zimmermann, The Washington Examiner, 5 Dec. 2025

In Tagovailoa’s defense, Miami’s offense line was a hot mess most of this season, until getting its act together the past five games, which has been a catalyst for the recent winning streak. —Miami Herald, 5 Dec. 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