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 Turner, in the first year of his four-year extension, has been playing out of position at the 4 on offense. J. Michael, Indianapolis Star, "Insider: Pacers passing on NBA trade deadline suggests they believe in Victor Oladipo," 7 Feb. 2020 The primary leadership of the Cayman Islands only found out a year later that its top-level extension already had an administrator. Michael Waters, Wired, "The Digital Colonialism Behind .tv and .ly," 7 Feb. 2020 Its current extension will expire after 2043, just as the Clean Energy Transformation Act takes full effect. oregonlive, "Power agency weighs building Northwest’s second nuclear reactor in eastern Washington," 2 Feb. 2020 Kevin Steele got his big contract extension this week, which is the best news Auburn has received since quarterback Bo Nix signed his letter of intent in 2018. Joseph Goodman | Jgoodman@al.com, al, "Gus Malzahn has the pieces in place to win big at Auburn," 24 Jan. 2020 Alex Bregman gets to keep his entire $100 million extension. Bob Nightengale, USA TODAY, "Opinion: Will the Houston Astros cheating scandal help Barry Bonds' and Rogers Clemens' Hall of Fame cases?," 20 Jan. 2020 If Antetokounmpo declines their contract extension next summer, the Bucks would be wise to wait until summer 2021 to deal him. Connor Letourneau, SFChronicle.com, "Giannis Antetokounmpo to the Warriors? It’s not as crazy as you might think," 7 Jan. 2020 The more Jones talks, the case for Garrett getting his second contract extension with the club, gets stronger. Calvin Watkins, Dallas News, "New year, same coach: Why Jerry Jones is taking his time to make a final decision about Jason Garrett," 1 Jan. 2020 So unless Mr Johnson is ready to ask for an extension, the risk of Britain leaving the EU with no trade deal in place at the end of next year will be significant. The Economist, "Boris Johnson’s big win," 13 Dec. 2019

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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Statistics for extension

Last Updated

12 Feb 2020

Cite this Entry

“Extension.” Merriam-Webster.com Dictionary, Merriam-Webster, https://www.merriam-webster.com/dictionary/extension?pronunciation&lang=en_us&dir=e&file=extens04. Accessed 17 Feb. 2020.

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More Definitions for extension


How to pronounce extension (audio)

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

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