ex·pan·sion | \ ik-ˈspan(t)-shən \

Definition of expansion 

1 : expanse

2 : the act or process of expanding territorial expansion economic expansion expansion of the universe

3 : the quality or state of being expanded

4 : the increase in volume of working fluid (such as steam) in an engine cylinder after cutoff or in an internal combustion engine after explosion

5a : an expanded part

b : something that results from an act of expanding the book is an expansion of a lecture series

6 : the result of carrying out an indicated mathematical operation : the expression of a function in the form of a series

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Other words from expansion

expansional \ik-ˈspanch-nəl, -ˈspan(t)-shə-nᵊl \ adjective

Examples of expansion in a Sentence

The league is undergoing expansion. the expansion of a lecture series into a book This book is an expansion of a lecture series.
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Recent Examples on the Web

Nor are those extra profits going into business expansion. Patricia Cohen, BostonGlobe.com, "Paychecks lag as profits soar, and prices erode wage gains," 14 July 2018 The expansion is expected to start next year, said Mr. Adam, with the first prototype dish built in China already on site about 280 miles north of Cape Town in the Northern Cape province. Wendell Roelf, The Christian Science Monitor, "South Africa's MeerKAT telescope will help uncover next space frontier," 13 July 2018 Northern Kentucky Tri-ED serves as the primary economic development entity for Boone, Campbell and Kenton counties providing marketing, business retention/expansion and entrepreneurship services for the region. Cincinnati Enquirer, Cincinnati.com, "Dan Tobertge resigns from Northern Kentucky Tri-ED," 13 July 2018 The Cherokee County Board of Commissioners has awarded a $1.59 million contract to Studio 8 Design for architectural and engineering services for the renovation and expansion of the Adult Detention Center in Canton. David Ibata, ajc, "Cherokee picks architect for detention center renovation," 13 July 2018 Here in Central Indiana, westward expansion has resulted in some truly fantastic towns and neighborhoods to call home. Shelley Specchio, Indianapolis Star, "Discovering Indianapolis’ vibrant neighborhoods: Hendricks County," 13 July 2018 More expansion is planned the following year with capacity ultimately doubling over several years. Gene Sloan, USA TODAY, "Exclusive events, all-inclusive fares: Inside the Tauck formula for small-ship cruising," 13 July 2018 Nor are those extra profits going into business expansion. Patricia Cohen, New York Times, "Paychecks Lag as Profits Soar, and Prices Erode Wage Gains," 13 July 2018 The bulk of current deforestation stems from massive agricultural expansion in the northeastern Brazilian states of Maranhão, Tocantins, Piauí and Bahia. Jeff Tollefson, Scientific American, "Deforestation Ticks Up in Brazil's Savanna," 13 July 2018

These example sentences are selected automatically from various online news sources to reflect current usage of the word 'expansion.' 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 expansion

1611, in the meaning defined at sense 1

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Statistics for expansion

Last Updated

1 Sep 2018

Look-up Popularity

Time Traveler for expansion

The first known use of expansion was in 1611

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More Definitions for expansion



English Language Learners Definition of expansion

: the act of becoming bigger or of making something bigger : the act of expanding

: a more complete and detailed written work or set of comments based on something shorter


ex·pan·sion | \ ik-ˈspan-shən \

Kids Definition of expansion

: the act of growing or increasing : enlargement


ex·pan·sion | \ ik-ˈspan-chən \

Medical Definition of expansion 

1 : the act or process of expanding

2 : the quality or state of being expanded

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Comments on expansion

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


a magnificent or impressive array

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