ensure
Americanverb (used with object)
verb
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(may take a clause as object) to make certain or sure; guarantee
this victory will ensure his happiness
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to make safe or secure; protect
Usage
What's the difference between ensure, insure, and assure? Ensure most commonly means to guarantee or make certain, as in Working hard ensures success. Insure typically means to guarantee against loss or harm or, more specifically, to cover with insurance. Assure usually means to tell someone something with confidence or to cause someone to know something with certainty—it often means the same thing as reassure. It’s no wonder there’s confusion between the three words—all three are verbs that are based on the Latin root sēcūrus, meaning safe. Making things even more confusing is the fact that ensure and insure can be used interchangeably in most senses. Still, insure is much more commonly used in the context of insurance, like car insurance, health insurance, and homeowner’s insurance. These kinds of insurance insure you—they give you coverage that provides you with compensation in certain cases and situations. Ensure is typically used in a more general way in the context of actions that are done to make sure that something happens or is the case, as in We need to ensure that the meeting starts on time. Assure is always used in the context of communication, especially in situations in which someone is trying to make someone else feel better about something. It’s used in the phrase rest assured. Here’s a quick cheat sheet to remember the most common uses of each word:ensure = make sureinsure = cover with insuranceassure = reassureHere’s an example of ensure, insure, and assure used correctly in a sentence. Example: She assured me that the company has ensured that every employee has the opportunity to be insured. Want to learn more? Read the full breakdown of the difference between ensure, insure, and assure.
Other Word Forms
Derived Forms
Inflected Forms
Participles
Conjugated Forms
Present
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ensuresimple
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ensuressimple
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have ensuredperfect
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has ensuredperfect
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am ensuringprogressive
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are ensuringprogressive
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is ensuringprogressive
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have been ensuringperfect progressive
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has been ensuringperfect progressive
Past
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ensuredsimple
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had ensuredperfect
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was ensuringprogressive
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were ensuringprogressive
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had been ensuringperfect progressive
Future
Etymology
Origin of ensure
First recorded in 1350–1400; Middle English ensuren, from Anglo-French enseurer; see en- 1 ( def. ), sure ( def. )
Explanation
When you ensure that something will happen, you guarantee it. All that homework will ensure that you have no time for fun this afternoon! Ensure comes from the Old French en- "make" plus seur "sure," and that is exactly what it means today - "to make sure or certain, to guarantee." If you ensure success or someone's safety, you are guaranteeing it. Make sure you can really come through with something before you ensure it!
Vocabulary lists containing ensure
Words to Know Before You Defrost the Bird
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"The Hunger Games" Vocabulary from Chapter 1
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Chains
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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.
Audit your vents and outdoor unit: Ensure furniture, rugs or curtains aren’t blocking indoor supply or return vents.
From MarketWatch • Jun. 29, 2026
Multiple Device Support: Ensure the VPN allows simultaneous connections on all your devices—phone, laptop, tablet, etc.
From Salon • Feb. 12, 2026
Two decades ago, when fake news actually meant fake, the Onion ran this headline: “Yankees Ensure 2003 Pennant By Signing Every Player In Baseball.”
From Los Angeles Times • Jan. 21, 2026
A sore spot in the third-quarter report was the company’s nutrition business, which sells the hydration drink Pedialyte, the adult therapeutic nutrition drink Ensure, and the infant formula brand Similac, among other products.
From Barron's • Oct. 15, 2025
“If you leave marks, it could cause an international incident. Archivist Werfel, take him collapsed to the room you’ve prepared for him. Watch him. Ensure that he recovers. Take good care of him.”
From "The Assassination of Brangwain Spurge" by M.T. Anderson and Eugene Yelchin
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.
