crucial
Americanadjective
-
involving an extremely important decision or result; decisive; critical.
a crucial experiment.
- Synonyms:
- significant, essential, vital, momentous
-
severe; trying.
-
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
Derived 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.
His final pitch was a crucial one, inducing an inning-ending double play with runners on the corners to hold the game at 1-0.
From Los Angeles Times • Jun. 6, 2026
He added that continued U.S. participation in the process is crucial for a new security architecture in the region.
From The Wall Street Journal • Jun. 5, 2026
The deal, which will bolster SpaceX's finances ahead of its IPO on June 12, covers a computing infrastructure of approximately 110,000 Nvidia GPUs -- the crucial hardware needed to power Google's Gemini AI models.
From Barron's • Jun. 5, 2026
"Our findings emphasize that understanding the coastal landscape as a whole is crucial when predicting how mangroves might respond to climate change, and how we can protect them."
From Science Daily • Jun. 5, 2026
He felt that he couldn’t lie if asked a direct question, and yet if he simply refused to answer, the assumption was that he was hiding something crucial.
From "Endgame" by Frank Brady
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.
