open up
Britishverb
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(intr) to start firing a gun or guns
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(intr) to speak freely or without restraint
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informal (intr) (of a motor vehicle) to accelerate
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(tr) to render accessible
the motorway opened up the remoter areas
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to make or become more exciting or lively
the game opened up after half-time
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Spread out, unfold, as in A green valley opened up before us . [Early 1800s]
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Begin operation, as in The new store opens up next month . [Late 1700s]
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Begin firing, begin attacking, as in The artillery opened up at dawn , or, figuratively, The speaker opened up fiercely on the opposition . [1930s] Also see open fire .
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Speak freely and candidly, as in At last the witness opened up and told what happened . “ Colloquial ; c. 1920]
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Make an opening by cutting, as in The surgeon opened up the patient's chest .
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Become available or accessible, as in With new markets opening up all the time we hope to see our revenues increase dramatically . [Mid-1800s]
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Increase the speed of a vehicle, as in Let's see how fast the car will go if you open it up . [ Colloquial ; c. 1920]
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Open the door, let me (or us) in, as in Open up! This is the police . [Mid-1900s] Note that in all of these usages except def. 4 and 7, up serves as an intensifier, that is, it emphasizes the verb open .
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.
He counts former central-bank governor Zhou Xiaochuan as a mentor and built his career on the premise that China’s financial system needed to open up, not wall itself off, to grow.
From The Wall Street Journal ● Jul. 24, 2026
Those core positions reduce portfolio volatility, open up space to take more risk in smaller positions and prevent emotional decisions at the worst possible time.
From MarketWatch ● Jul. 22, 2026
Boreal forests are also supposed to burn on an infrequent basis, in order to open up certain pine cones and spread their seeds, or to clear out lower tree branches.
From Slate ● Jul. 21, 2026
“They open up the restaurant with no roof on it. There’s no air conditioning unit. It was the hottest day,” says Katerina.
From Los Angeles Times ● Jul. 14, 2026
Then I open up my laptop, search for “white spots on skin,” and click on the first result.
From "How to Disappear Completely" by Ali Standish
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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.