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 Scooter Gennett went to arbitration hearings with the Reds in 2018, but Suárez signed a long-term extension shortly afterward. Bobby Nightengale, Cincinnati.com, "Cincinnati Reds avoid arbitration with all players; Trevor Bauer nets near-record deal," 10 Jan. 2020 PayPal Holdings made a big bet in November with its $4 billion acquisition of Honey, a web browser extension that helps online shoppers find the lowest prices. Julie Verhage, Fortune, "Experts Question Amazon’s Warning About Honey, PayPal’s E-Commerce Shopping Tool," 10 Jan. 2020 Former Auburn quarterback Nick Marshall signed a one-year contract extension with the Saskatchewan Roughriders on Wednesday, the Canadian Football League team announced. Mark Inabinett | Minabinett@al.com, al, "Nick Marshall re-signs with CFL’s Saskatchewan Roughriders," 8 Jan. 2020 Each wants to sign long-term contract extensions with the Colts. Jim Ayello, Indianapolis Star, "Insider: A step-by-step examination of Chris Ballard's offseason to-do list," 5 Jan. 2020 The shell of the service station has survived, augmented by a large extension stretching almost to street-side. Eric E. Harrison, Arkansas Online, "Little Rock's year in food," 31 Dec. 2019 The right-hander avoided arbitration by officially signing a contract extension for three years and $13 million, with a club option worth $8 million for 2023. Patrick Saunders, The Denver Post, "Rockies’ Scott Oberg gets big money and good news on same day," 11 Dec. 2019 But very few of Boras’ clients sign extensions before free agency. Mark Gonzales, chicagotribune.com, "Kris Bryant’s agent, Scott Boras, says ‘our ears are open’ to a long-term extension with the Cubs, but they’re also preparing for other scenarios," 10 Dec. 2019 Franklin later signed a contract extension with the Nittany Lions. Luis Torres, orlandosentinel.com, "FSU leaders say slower search was key to landing right coach in Mike Norvell," 9 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

15 Jan 2020

Cite this Entry

“Extension.” The Merriam-Webster.com Dictionary, Merriam-Webster Inc., https://www.merriam-webster.com/dictionary/extensions. Accessed 19 January 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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Comments on extension

What made you want to look up extension? Please tell us where you read or heard it (including the quote, if possible).


to insert between existing elements

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