[ en-shoor, -shur ]
/ ɛnˈʃʊər, -ˈʃɜr /
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See synonyms for: ensure / ensured / ensures / ensuring on Thesaurus.com

verb (used with object), en·sured, en·sur·ing.
to secure or guarantee: This letter will ensure you a hearing.
to make sure or certain: measures to ensure the success of an undertaking.
to make secure or safe, as from harm.
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Origin of ensure

1350–1400; Middle English ensuren<Anglo-French enseurer.See en-1, sure


en·sur·er, nounun·en·sured, adjective
Dictionary.com Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2023


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 sure
insure = cover with insurance
assure = reassure

Here’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.

Quiz yourself on ensure vs. insure vs. assure!

Should ensure, insure, or assure be used in the following sentence?

We need to take action to _____ that this never happens again.

How to use ensure in a sentence

British Dictionary definitions for ensure


esp US insure

/ (ɛnˈʃʊə, -ˈʃɔː) /

verb (tr)
(may take a clause as object) to make certain or sure; guaranteethis victory will ensure his happiness
to make safe or secure; protect

Derived forms of ensure

ensurer, noun
Collins English Dictionary - Complete & Unabridged 2012 Digital Edition © William Collins Sons & Co. Ltd. 1979, 1986 © HarperCollins Publishers 1998, 2000, 2003, 2005, 2006, 2007, 2009, 2012