ex·​ten·​sion | \ ik-ˈsten(t)-shən How to pronounce extension (audio) \

Definition of extension

1a : the action of extending : state of being extended
b : an enlargement in scope or operation tools are extensions of human hands
2a : the total range over which something extends : compass
3a : the stretching of a fractured or dislocated limb so as to restore it to its natural position
b : an unbending movement around a joint in a limb (such as the knee or elbow) that increases the angle between the bones of the limb at the joint — compare flexion sense 4a
4 : a property whereby something occupies space
5 : an increase in length of time specifically : an increase in time allowed under agreement or concession
6 : a program that geographically extends the educational resources of an institution by special arrangements (such as correspondence courses) to persons otherwise unable to take advantage of such resources
7a : a part constituting an addition
b : a section or line segment forming an additional length
c : an extra telephone connected to the principal line
d : a length of natural or synthetic hair that is worn attached to one's natural hair
e : a series of usually three or four characters following a dot at the end of the name of a computer file that specifies the file's format or purpose
8 : a mathematical set (such as a field or group) that includes a given and similar set as a subset

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Examples of extension in a Sentence

extension of the patient's life He's asking for a contract extension. Make sure that the muscles get the proper amount of extension. I missed the deadline but was granted an extension.
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Recent Examples on the Web Each restaurant or event that the couple do is an extension of their artistic practices, and a thorough one at that. New York Times, 23 July 2021 Now, Dropbox is adding some of those: a Dropbox Passwords browser extension to save and fill in passwords, the ability to share passwords, and even the ability to store credit and debit cards in Dropbox Passwords, too. Mark Hachman, PCWorld, 20 July 2021 Another extension, this time to Dec. 31, 2020, was negotiated, but never finalized, the groups said in the suit. Sarah Freishtat, chicagotribune.com, 9 July 2021 Babcock also recommends keeping the color scheme as an extension of the rest of the home, which can create the illusion of more space simply by way of cohesion. Jennifer Tzeses, Harper's BAZAAR, 7 July 2021 Araujo’s extension, which will be announced Tuesday morning, is the Galaxy’s first signing under the U-22 initiative, which allows teams to sign up to three players aged 22 and younger to lucrative contracts at a reduced budget charge. Kevin Baxter, Los Angeles Times, 6 July 2021 Terms of the contract extension, which was first reported by D1Baseball, were not immediately available. James Crepea | The Oregonian/oregonlive, oregonlive, 5 July 2021 In 2016, for example, the NCAA negotiated an eight-year extension of its broadcasting rights to March Madness, worth $1.1 billion annually. Douglas S. Wood And David Close, CNN, 4 July 2021 Ryan Ramczyk has signed a $96 million extension, or a little more than $10 million per consonant. Nick Canepa Columnist, San Diego Union-Tribune, 3 July 2021

These example sentences are selected automatically from various online news sources to reflect current usage of the word 'extension.' Views expressed in the examples do not represent the opinion of Merriam-Webster or its editors. Send us feedback.

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First Known Use of extension

15th century, in the meaning defined at sense 1a

History and Etymology for extension

Middle English, from Late Latin extension-, extensio, from Latin extendere

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Time Traveler for extension

Time Traveler

The first known use of extension was in the 15th century

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Dictionary Entries Near extension



extension agent

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Last Updated

26 Jul 2021

Cite this Entry

“Extension.” Merriam-Webster.com Dictionary, Merriam-Webster, https://www.merriam-webster.com/dictionary/extension. Accessed 27 Jul. 2021.

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More Definitions for extension



English Language Learners Definition of extension

: the act of making something longer or greater
: the act of straightening or stretching something (such as an arm or a leg)
: extra time allowed for doing something


ex·​ten·​sion | \ ik-ˈsten-shən How to pronounce extension (audio) \

Kids Definition of extension

1 : the act of making something longer or greater extension of the sail
2 : an increase in length or time
3 : a part forming an addition or enlargement


ex·​ten·​sion | \ ik-ˈsten-chən How to pronounce extension (audio) \

Medical Definition of extension

1 : the stretching of a fractured or dislocated limb so as to restore it to its natural position
2 : an unbending movement around a joint in a limb (as the knee or elbow) that increases the angle between the bones of the limb at the joint — compare flexion sense 1

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Legal Definition of extension

: an increase in length of time specifically : an increase in the time allowed under an agreement

More from Merriam-Webster on extension

Nglish: Translation of extension for Spanish Speakers

Britannica English: Translation of extension for Arabic Speakers

Britannica.com: Encyclopedia article about extension


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