ensure
Americanverb
-
(may take a clause as object) to make certain or sure; guarantee
this victory will ensure his happiness
-
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
- ensurer noun
- unensured adjective
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
Looking to grow your vocabulary? Check out this interactive, curated word list from our team of English language specialists at Vocabulary.com – one of over 17,000 lists we've built to help learners worldwide!
"The Hunger Games" Vocabulary from Chapter 1
Interested in learning more words like this one? Our team at Vocabulary.com has got you covered! You can review flashcards, quiz yourself, practice spelling, and more – and it's all completely free to use!
Chains
Want to remember this word for good? Start your learning journey today with our library of interactive, themed word lists built by the experts at Vocabulary.com – we'll help you make the most of your study time!
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.
Breeden said her job was not to predict when and how much the markets fall but to ensure the financial system is ready if it does.
From BBC • Apr. 23, 2026
The ideas I’ve outlined are only the beginning—pieces of a broader economic-growth strategy to ensure our country’s global pre-eminence for generations to come.
From The Wall Street Journal • Apr. 23, 2026
Everyone underestimates Ashley’s intelligence and Austin’s willingness to sell out justice to ensure they’ll get ahead.
From Salon • Apr. 23, 2026
"Efforts continue to broaden participation and ensure that the mission is equipped with the capabilities required to fulfill its mandate," Christofides said.
From Barron's • Apr. 23, 2026
The world had learned the hard way that ruthless justice was the only way to ensure that the past remained untampered with.
From "Glitch" by Laura Martin
![]()
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.