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Catalyst

KAT-uh-list /ˈkætəlɪst/

nounC1GRESATGMAT

formalscientificbusiness

A substance that increases the rate of a chemical reaction without itself undergoing any permanent chemical change; also, a person or thing that precipitates an event.

In chemistry, it's a specific chemical agent. In general use, it's an initiator or accelerator of change.

The story behind the word. The word 'catalyst' comes from the Greek 'katalysis,' meaning 'dissolution' or 'a loosening.' It's formed from 'kata-' (down) and 'lysis' (a loosening or dissolving). The term was introduced into chemistry in the 19th century by Jöns Jacob Berzelius to describe substances that 'loosen' or speed up chemical reactions without being used up themselves. Its broader meaning of 'an agent of change' developed later.

Word relationships

accelerator: Emphasizes speeding up, but less formal than catalyst in scientific contexts.
impetus: The force or energy that makes something happen or happen more quickly.
stimulus: Something that causes a reaction, but doesn't necessarily speed up an existing process.

inhibitor: A substance that slows down or prevents a chemical reaction.
deterrent: Something that discourages or prevents an action.

Commonly confused with

Reagent: A reagent is a substance used to cause a chemical reaction; a catalyst speeds it up without being consumed.

Word family

catalyze (verb): To cause or accelerate a reaction or process.
catalytic (adjective): Relating to or involving catalysis.

Collocations

biological catalyst
industrial catalyst
catalyst for change
economic catalyst

Example sentences

"The enzyme acts as a biological catalyst, speeding up the digestion of food." In a chemical context.
"Her passionate speech was the catalyst for the widespread social movement." Referring to an event or person.
"Platinum is often used as a catalyst in catalytic converters to reduce harmful emissions from vehicles." From an industrial application.

Memory hook

Think of a 'CAT-alyst' as a 'CAT' that 'LISTS' all the things to do to speed up a reaction, but doesn't do them itself. CAT-alyst: CAT LISTS speed-ups

When not to use

Do not use 'catalyst' if the substance or person is consumed or fundamentally changed by the process they initiate.

Fun facts

The catalytic converter in cars uses platinum, palladium, and rhodium as catalysts to convert harmful pollutants into less toxic substances.
Enzymes are highly specific biological catalysts, each designed to speed up a particular biochemical reaction.