crucial
Americanadjective
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involving an extremely important decision or result; decisive; critical.
a crucial experiment.
- Synonyms:
- significant, essential, vital, momentous
-
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
-
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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Jim Burke's Academic Vocabulary List
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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.
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
Understanding the evolutionary response to climate change is crucial to conserving the world’s primates, and other species beyond.
From Science Daily • Jun. 20, 2026
Pouring rain hasn't dampened the spirits of Scotland fans as they prepare to watch a crucial World Cup match at the country's biggest music festival.
From BBC • Jun. 19, 2026
The closure of the strait during the war drove up global oil prices and choked off shipments of energy and crucial commodities such as fertiliser.
From Barron's • Jun. 19, 2026
Frank was trained as a waiter and later became Mount Vernon’s head butler, a crucial and prestigious job in a household like Washington’s.
From "In the Shadow of Liberty" by Kenneth C. Davis
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.
