crucial
Americanadjective
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involving an extremely important decision or result; decisive; critical.
a crucial experiment.
- Synonyms:
- significant, essential, vital, momentous
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severe; trying.
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of the form of a cross; cross-shaped.
adjective
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involving a final or supremely important decision or event; decisive; critical
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informal very important
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slang very good
Usage
What does crucial mean? Crucial means extremely important or involving an extremely important decision or course of action. Close synonyms are critical and decisive. The word crucial is usually used to describe pivotal moments, choices, or actions that will affect everything that follows, as in We’re at a crucial point in the process—we need to make some big decisions. Sometimes, crucial is simply used to describe something that’s extremely important, as in Getting enough sleep is crucial for staying healthy. Example: I can’t express how absolutely crucial it is to surround yourself with the right friends.
Other Word Forms
Etymology
Origin of crucial
First recorded in 1700–10; from Latin cruci- (stem of crux cross ( def. ) ) + -al 1 ( def. )
Explanation
The word crucial describes something that is important or essential to success, like the crucial dress rehearsals that ensure everything will run smoothly on your play's opening night. Usage experts insist that the word crucial should be used only to describe something that is truly critical for solving a problem or for resolving a situation, such as a crucial vote that determines a final outcome. In this case the crucial vote is decisive: it determines the outcome. But the word has gained popularity as a way to say that something is important. You might hear someone say, for example, that it is crucial to allow employees to vote on the new schedule to make them feel like they’re part of the process. In this case the sense is “important”: nothing decisive is taking place.
Vocabulary lists containing crucial
List 1
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Walk Two Moons
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Example Sentences
Examples are provided to illustrate real-world usage of words in context. Any opinions expressed do not reflect the views of Dictionary.com.
One crucial question which is already the subject of intense speculation is the matter of who Burnham would appoint as chancellor.
From BBC • Jun. 21, 2026
China is Iran’s biggest oil client, and Chinese banks are crucial in moving proceeds from the sales to Iranian front companies to buy goods and services in China, Western officials say.
From The Wall Street Journal • Jun. 21, 2026
Myung-bo said that during the pre-match talk, he emphasized that the first 20 minutes would be crucial and believed his players had executed that part of the plan.
From Los Angeles Times • Jun. 20, 2026
Identifying those subgenomes is crucial for understanding how a species evolved.
From Science Daily • Jun. 19, 2026
And ear training is also crucial for those interested in music theory, musicology, or just being able to write down a tune accurately.
From "Understanding Basic Music Theory" by Catherine Schmidt-Jones and Russel Jones
Definitions and idiom definitions from Dictionary.com Unabridged, based on the Random House Unabridged Dictionary, © Random House, Inc. 2023
Idioms from The American Heritage® Idioms Dictionary copyright © 2002, 2001, 1995 by Houghton Mifflin Harcourt Publishing Company. Published by Houghton Mifflin Harcourt Publishing Company.
